ESGAR 2017 Book of Abstracts

Insights into Imaging, May 2017

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ESGAR 2017 Book of Abstracts

SCIENTIFIC SESSIONS / WEDNESDAY, JUNE into Imaging Education and strategies in European radiology 0 Prof. Panagiotis Prassopoulos University Hospital of Alexandroupolis Medical School of Thrace Department of Radiology Dragana GR - 68100 Alexandroupolis - ESGAR 2017 / June 20 – 23 / Athens, Greece 28th Annual Meeting and Postgraduate Course Society ATHENS of Gastrointestinal and Abdominal GREECE Radiology ORGANISING SECRETARIAT Central ESGAR Office Neutorgasse 9 AT – 1010 Vienna Phone: +43 1 535 89 27 Fax: +43 1 535 89 27 -15 E-Mail: of  WEBSITE www.esgar.org CME CREDITS The ‘ESGAR European Society of Gastrointestinal and Abdominal Radiology’ (or) ‘ESGAR 2017 – 28 th ANNUAL MEETING AND POSTGRADUATE COURSE’ is accredited by the European Accreditation Council for Continuing Medical Education (EACCME) to provide the following CME activity for medical specialists. The EACCME is an institution of the European Union of Medical Specialists (UEMS), www.uems.net. CONTRIBUTING SOCIETIES CONFERENCE VENUE Megaron Athens International Conference Centre MAICC Vas. So as Ave. & Kokkali GR – 11521 Athens The ‘ESGAR 2017 – 28th ANNUAL MEETING AND POSTGRADUATE COURSE’ is designated for a maximum of (or ‘for up to’) 24 hours of European external CME credits. Each medical specialist should claim only those hours of credit that he/she actually spent in the educational activity. ESGAR wishes to gratefully acknowledge the support of its Corporate Members: The Final Programme of ESGAR 2017 is available on the ESGAR Website www.esgar.org Date of publishing: June 2017 TABLE OF CONTENTS Scienti c Sessions, Wednesday, June 21 (SS 1–SS 4) Scienti c Sessions, Thursday, June 22 (SS 5–SS 9) Scienti c Sessions, Friday, June 23 (SS 10–SS 14) ESGAR EXECUTIVE COMMITTEE PRESIDENT C. Matos, Lisbon/PT PRESIDENT-ELECT S. Halligan, London/GB VICE PRESIDENT R.G.H. Beets-Tan, Amsterdam/NL SECRETARY A. Palkó, Szeged/HU TREASURER S. Jackson, Plymouth/GB PAST PRESIDENT L. Martí-Bonmatí, Valencia/ES EDUCATION COMMITTEE R.G.H. Beets-Tan, Amsterdam/NL MEMBERSHIP COMMITTEE T. Helmberger, Munich/DE WORKSHOP COMMITTEE G. Brancatelli, Palermo/IT MEETING PRESIDENT P. Prassopoulos, Alexandroupolis/GR PRE-MEETING PRESIDENT H. Fenlon, Dublin/IE PAST MEETING PRESIDENT V. Valek, Brno/CZ MEMBERS AT LARGE A. Laghi, Latina/IT J. Stoker, Amsterdam/NL M. Zins, Paris/FR ESGAR EXECUTIVE DIRECTOR B. Lindlbauer, Vienna/AT LANGUAGE ABSTRACT EDITOR C. Clarke, Leeds/GB ESGAR 2017 MEETING PRESIDENT ESGAR 2017 PROGRAMME COMMITTEE CHAIRMAN L. Martí-Bonmatí, Valencia/ES V. Valek, Brno/CZ ESGAR 2017 LOCAL ORGANISING COMMITTEE V. Koutoulidis, Athens/GR I. Bargellini, Pisa/IT V. Cantisani, Rome/IT V. Goh, London/GB V. Maniatis, Aabenraa/DK V. Valek, Brno/CZ V. Vilgrain, Clichy/FR Alexandra Trianti Hall Scienti c Session SS 1 Best rated papers on advanced imaging of pancreatic tumours SS 1.1 Pancreatic adenocarcinoma: preoperative imaging biomarker for predicting prognosis after curative resection S. Lee, S.H. Kim; Seoul/KR Purpose: To identify magnetic resonance (MR) imaging features that could predict prognosis in patients with curative resection of pancreatic adenocarcinoma. Material and methods: This retrospective study was approved by the institutional review board, and informed consent requirement was waived. A total of 143 patients who underwent R0 resection and MR imaging for pancreatic adenocarcinoma were included. Two radiologists, blinded to the clinical data, evaluated in consensus the imaging pattern and signal intensity on dynamic phase images. We assessed predictive factors for disease-free survival (DFS) and overall survival (OS). Results: Tumor size (hazard ratio (HR), 1.318; P  = .003 and HR, 1.437; P  < .001) and rim enhancement (HR, 1.726; P = .029 and HR, 2.267; P = .001) were independent prognostic factors for DFS and overall survival OS. The grade of differentiation (P = .004) was worse and serum level of carbohydrate antigen 19-9 (P = .045) was higher in pancreatic adenocarcinomas with rim enhancement than those without rim enhancement. The log-rank test (P =.008 and P = .001) revealed that pancreatic adenocarcinomas without rim enhancement had signi cant longer DFS and OS. Conclusion: The results suggest that pancreatic adenocarcinomas with rim enhancement are more aggressive than those without rim enhancement. Rim enhancement on MR imaging may be a useful imaging biomarker to predict prognosis in patients with curative resection of pancreatic adenocarcinoma. SS 1.2 Contrast-enhanced perfusion MRI at 3T device of solid pancreatic lesions: qualitative and quantitative analysis F. Donati, P. Boraschi, R. Cervelli, F. Pacciardi, C. Lombardo, U. Boggi, F. Falaschi, D. Caramella; Pisa/IT Purpose: To assess the usefulness of contrast-enhanced perfusion MRI (CEPMRI) at 3T-device of solid pancreatic lesions, by performing qualitative and quantitative analysis. Material and methods: Ten patients without pancreatic disease and twenty ve with pathologically con rmed pancreatic lesions (ductal adenocarcinoma, n=14; endocrine tumor, n=8; mass-forming pancreatitis, n=3), underwent MR imaging at 3T-device (GE DISCOVERY MR750; GE Healthcare). Multiphasic CEP-MRI consisted of a 3D axial navigator-based free-breathing T1-weighted DISCO sequence repeated up to 5 minutes to cover the entire pancreas. A dose of 0.1 mL/kg of Gadobutrolo (Gadovist; Bayer HealthCare) with a 20 mL saline ®ush was injected at a ®ow rate of 5 mL/s. Perfusion MR images were processed using a dedicated software (GeniQ;GE Healthcare) by two experienced reviewers in conference, obtaining both a time-signal-intensity curve (TSIC) and a perfusion map for the normal pancreatic parenchyma and for each focal lesion, on the basis of which they classi ed four TSIC shapes and calculated the perfusion MRI parameters (Ktrans, Kep, Ve, IAUGC). Results: All 10 patients with normal pancreas presented a TSIC-type1. TSICtype2 was observed in all 14 ductal adenocarcinomas and in 1 endocrine tumor; TSIC-type3 was recognized in the remaining 7 patients with endocrine neoplasms; TSIC-type4 was identi ed in all 3 mass-forming pancreatitis. All perfusion parameters were signi cantly different (p<0.0001) for each type of lesion; furthermore, Ve was very helpful to discriminate between normal and pathological tissue (p=0.0005). Conclusion: Qualitative and quantitative analysis of CEP-MRI at 3T-device could improve the diagnosis of solid pancreatic lesions. SS 1.3 The relationship between pre-operative imaging to surgery interval and survival in pancreatic adenocarcinoma G.M. Healy, C.E. Redmond, S. Murphy, H.A. Fleming, A. Haughey, R.G. Kavanagh, D. Malone, E.R. Ryan; Dublin/IE Purpose: Recent evidence indicates that longer pre-operative imaging to surgery time interval (ISI) for pancreatic ductal adenocarcinoma (PDAC) increases the risk of unexpected progression (UP) at laparotomy. We assessed the relationship between ISI and survival. Material and methods: Retrospective review of all patients who underwent attempted resection of PDAC at our institution between January 2010 and December 2015. Patients who received neoadjuvant therapy were excluded. All were followed up until 31st June 2016. Survival was determined from the national death register. The population was divided based upon ISI ≥ or < 25 days. Kaplan Meier survival analysis was performed. Results: 240 patients were classi ed as resectable on pre-operative abdominal CT and underwent laparotomy. UP was found in 30 (13%) cases. The ISI was longer for patients with UP compared to those without (51.7 vs 35.1 days, p<0.05). When intention-to-treat analysis was performed, there was no difference in survival between patients with ISI ≥ 25 (median 19.8 months) vs < 25 (12.6 months), however, in those who underwent resection, an ISI ≥25 days was associated with longer survival (25.2 vs 19.6 months, p<0.05). Conclusion: Performing surgery for PDAC within 25 days of pre-operative abdominal CT reduces risk of UP, however, this does not improve survival. In fact, longer ISI is associated with survival advantage for those who are resected. Lack of progression over a longer pre-operative ISI likely indicates more indolent disease. SS 1.4 3D-CT texture analysis of neuroendocrine pancreatic neoplasms M. D’Onofrio1, V. Ciaravino1, N. Cardobi2, R. De Robertis2, S. Cingarlini1, P. Capelli1, L. Landoni1, A. Scarpa1; 1Verona/IT, 2Peschiera del Garda/IT Purpose: To evaluate the added value of CT texture analysis in the study of neuroendocrine pancreatic neoplasms. Material and methods: 24 patients with neuroendocrine pancreatic neoplasms were included in this study. All tumors were pathologically diagnosed after resection or by means of biopsy. Histological grade of these neoplasms was available in all cases. There were 7 G1, 7 G2, and 10 G3 neoplasms with presence of metastases in 21/24 (87%) cases. Three-dimensional CT texture analysis of the primary tumor was performed comparing the results with the tumor grading using Wilcoxon correlation test. Results: Pancreatic neoplasms were located in the head in 7/24 (29%) cases; in the body-tail in 17/24 (71%) cases. G1 neoplasms show mean dimension of 41 mm (range 9-112 mm). G2 neoplasms show mean dimension of 42 mm (range 21-73 mm). G3 neoplasms show mean dimension of 50 mm (range 16111 mm). CT texture analysis was  nalized in all cases. There was no statistical signi cant difference regarding all the parameters of CT texture analysis among G1, G2, and G3 neoplasms. Higher value of kurtosis was found in G3 (Kurtosis median=2,1499000) in respect to G1 (Kurtosis median=0,1128400) and G2 (Kurtosis median=1,3848000) neoplasms. Grouping together G1 and G2 neoplasms, statistical signi cant difference (p< 0,05) was found regarding the only kurtosis CT texture analysis parameter. Conclusion: This preliminary results show that CT texture analysis parameters can be complementary data for neuroendocrine pancreatic neoplasms grade prediction. SS 1.5 Histogram analysis of ADC maps: assessment of intra-tumoral heterogeneity and correlation with the biological behavior of pancreatic neuroendocrine neoplasms R. De Robertis1, N. Cardobi1, B. Maris2, P. Tinazzi Martini1, S. Ortolani1, S. Cingarlini2, G. Butturini1, S. Gobbo1, L. Landoni2, P. Fiorini2, G. Tortora2, A. Scarpa2, M. D‘Onofrio2; 1Peschiera del Garda/IT, 2Verona/IT Purpose: To evaluate the relationship between tumor heterogeneity assessed through the histogram analysis of apparent diffusion coef cient (ADC) maps and the biological behavior of pancreatic neuroendocrine neoplasms (PanNENs). Material and methods: Pre-operative MR examinations of 34 patients with PanNENs were retrospectively reviewed. Regions of interest were drawn on every section of the ADC map containing the tumor; histograms for entire tumor volume were obtained. Histographic parameters included mean and median ADC, standard deviation, minimum and maximum ADC (maxADC), 25th-, 75th- and 95th-percentile ADC, interquartile range, skewness, kurtosis, variance, entropy, and uniformity. Student’s T tests for independent samples were conducted to compare between histogram-derived parameters and histopathological features. ROC curves were calculated to identify the most predictive histogram-derived parameters. Results: Kurtosis was signi cantly higher in low-grade PanNENs and tumors with vascular in ltration compared to G1 and less-aggressive tumors (5.06 vs 2.87 and 6.5 vs 3.55, p=0.023 and 0.05; AUC=0.764 and 0.867). Entropy was signi cantly higher in tumors with nodal metastases compared to N0 tumors (8.09 vs 5.57, p=0.001; AUC=0.800). MaxADC was signi cantly higher in tumors with liver metastases compared to those without liver metastases (2841 vs 2155.72, p=0.027; AUC=0.821). Conclusion: Intratumoral heterogeneity is higher in high-grade PanNENs and in tumors with vascular in ltration and nodal metastases compared to PanNENs with less-aggressive clinical behavior. PanNENs with liver metastases have higher maxADC values compared to M0 tumors. Scienti c Session SS 2 Malignant liver lesions: best diagnostic and therapeutic approaches SS 2.1 Multiparametric 3T MRI versus contrast-enhanced CT for the preoperative staging of colorectal liver metastases after chemotherapy: the influence on the surgical planning P. Boraschi, F. Donati, F. Pacciardi, R. Cervelli, L. Urbani, M. Castagna, F. Falaschi, D. Caramella; Pisa/IT Purpose: To evaluate the diagnostic performance of multiparametric 3T MRI and contrast-enhanced CT (CE-CT) in the preoperative staging of colorectal liver metastases in patients previously undergoing neoadjuvant chemotherapy (nCT). Material and methods: Fifty-eight patients affected by colorectal cancer and focal liver lesions underwent multiphasic multidetector CE-CT and multiparametric 3T MRI after nCT, one month before parenchymal-sparing surgery. At MRI unenhanced (T1- and T2-weighted), DWI with multiple b-values (150,500,1000,1500 sec/mm³) and both dynamic and hepatobiliary phases (Gd-EOB-DTPA) were obtained. All CT and MR examinations were reviewed by two observers in conference in order to detect and characterize focal liver lesions. CT and MRI  ndings were related with histopathology, which was our gold standard. Only benign lesions at intraoperative ultrasound remained unresected and underwent imaging follow-up. Results: A total of 370 hepatic lesions were detected: 292 metastases (79%) and 78 benign lesions. At MRI 359/370 (97.0%) lesions were detected, whereas at CT 245/370 (66.2%) were identi ed. The sensitivity, speci city, PPV, NPV of MRI and CT metastases characterization were 98.9%, 97.3%, 99.3%, 96.0%, and 87.6%, 41.3%, 82.7%, 51.0%, respectively. The higher yield of MRI has improved the surgical planning in 37/58 patients (63.8%) compared to CE-CT. Conclusion: Multiparametric 3T MRI may provide better diagnostic performance than CE-CT for the detection and characterization of colorectal liver metastases after nCT. It can also potentially improve the surgical planning in over 60% of patients. SS 2.2 Diagnosis of hepatocellular carcinoma with gadoxetic acid-enhanced MRI: 2016 consensus recommendations of the Korean Society of Abdominal Radiology (KSAR) M.-S. Park, Seoul/KR Purpose: Diagnosis of HCC with EOB-MRI poses certain unique challenges beyond the scope of current guidelines. The KSAR reached consensus on several issues of debate from the radiologists’ point of view, based on routine clinical practices. Material and methods: 5 organizing members extract debatable issues that were deemed essential for diagnosis of HCC by EOB-MRI. 4 panels comprising 21 panelists consolidated relevant evidences regarding their assigned issues and prepared a draft of a speci c questionnaire. The initial 34 questions were presented to members of the KSAR. We used a modi ed Delphi method. Results: Consensus was reached on 12 statements. The key statements are as follows: noninvasive diagnostic criteria for HCC with EOB-MRI in Korea should aim for early detection and high sensitivity, while maintaining acceptable speci city; washout appearance should be determined on either the portal venous or transitional phase of EOB-MRI; sub-centimeter-sized HCC may be diagnosed by EOB-MRI by applying additional re ned diagnostic criteria in addition to the typical vascular pro le changes. Nodules of sizes ranging from 1 to 2 cm and those of sizes >2 cm do not require separate diagnostic criteria. The de nition of capsular appearance on EOB-MR images should be different from that on extracellular contrast media-based MR images. Conclusion: Although several challenges remain in terms of optimization and standardization, these consensus recommendations might serve as useful tools to ensure more standardized diagnosis of HCC by EOB-MRI. SS 2.3 Pathological feature of hepatocellular carcinomas showed ring-like enhancement on all phases of multiphasic dynamic magnetic resonance imaging S. Ichikawa1, U. Motosugi1, N. Oishi1, T. Wakayama2, H. Onishi1; 1Yamanashi/JP, 2Tokyo/JP Purpose: To evaluate pathological features of hepatocellular carcinomas (HCCs) which showed ring-like enhancement in all phases of multiphasic hepatic arterial phase (HAP) imaging (6 phases). Material and methods: This study included 35 surgically proven HCCs in 30 patients, who were examined by gadoxetic acid-enhanced MRI using differential sub-sampling with Cartesian ordering (DISCO). Multiphasic HAP imaging was started at 30s after the injection and completed within a single breathhold (acquisition time=22–26s, temporal resolution=~4s). The HCCs were classi ed per their enhancement patterns: ring-like enhancement in all phases (group A; n=7) and total enhancement in any phase (group B; n=28). A single pathologist evaluated the ratio of poorly differentiated component and necrosis, and thickness of the capsule for all nodules. Results: The ratio of necrosis was signi cantly higher ( p=0.0006) in group A (mean (median, range)); (41.4 (30.0, 0–90.0)%) than in group B (3.0 (0, 0–25.0)%). The capsules were signi cantly thicker ( p=0.0108) in group A (0.52 (0.55, 0.12–0.9) mm) than in group B (0.26 (0.25, 0–0.76) mm). All the nodules of group A had capsule, while seven nodules in group B (25%) had no capsule. There were no signi cant differences in tumor size and ratio of poorly differentiated component. Conclusion: The HCCs represented by ring-like enhancement on all phases of DISCO had more necrosis and thicker capsules compared to classical HCCs. SS 2.4 Association between non-hypervascular hypointense nodules on gadoxetic acid-enhanced MRI and hepatic fibrosis or hepatocellular carcinoma J.A. Hwang, T.W. Kang, J.E. Lee, Y.K. Kim, S.H. Kim; Seoul/KR Purpose: The risk factors for the occurrence of non-hypervascular hypointense nodules (NHHN) on gadoxetic acid-enhanced magnetic resonance imaging (MRI) are still unclear. We assessed the association between these nodules and hepatic  brosis or hepatocellular carcinoma (HCC) in patients with chronic liver disease, and analyzed their progression to overt HCC. Material and methods: Between August 2012 and March 2016, 714 consecutive patients who had undergone transient elastography for liver stiffness (LS) measurement and gadoxetic acid-enhanced MRI were investigated. The association between the presence of NHHN on the hepatobiliary phase and LS, and the patient’s HCC status was assessed using multivariate logistic analysis. In patients with these nodules, cumulative progression rates of nodules to overt HCC were compared with rates of new HCC development in other parts of the liver using the strati ed log-rank test. Results: The prevalence of NHHN was 16.8% (120/714). The presence of NHHN was signi cantly associated with the log LS (Odds ratio [OR], 1.48,  p = 0.002) and hepatitis B virus infection (OR, 3.14, p = 0.017). The two-year cumulative progression rate of overt HCC from NHHN and rate of progression to HCC in other parts of the liver were 34.1% and 18.3%, respectively (p = 0.071). Conclusion: The presence of NHHN was not associated with the patient’s HCC status but was associated with hepatic  brosis and hepatitis B virus infection. Furthermore, these lesions frequently progressed to overt HCC. SS 2.5 Adding intratumoral pathomorphologic ancillary features to conventional enhancement patterns of hepatocellular carcinoma on gadoxetic acid-enhanced MR imaging improves diagnostic performance Y.K. Kim, J.H. Min, W.K. Jeong; Seoul/KR Purpose: To assess the added value of intratumoral ancillary features to enhancement pattern-based diagnosis of hepatocellular carcinoma on gadoxetic acid-enhanced MRI. Material and methods: A total of 773 consecutive patients with surgically resected 773 primary hepatic tumors (699 HCCs, 63 intrahepatic cholangiocarcinomas, and 11 benign nodules) who underwent gadoxetic acid MRI were retrospectively identi ed. Enhancement patterns and three ancillary features of capsule, septum and T2 spotty hyperintensity were assessed by two radiologists. Performance of enhancement pattern-based diagnosis of HCC was compared to diagnosis with enhancement pattern plus ancillary features. Results: Enhancement patterns were positive (arterial hyperenhancement with washout) for 562 (72.7%) tumors, negative (no arterial hyperenhancement and no washout) for 75 (9.7%), and inconclusive (either no arterial hyperenhancement or no washout) for 136 (17.6%). Capsule was observed in 498 (64.4%) tumors, septum in 521 (67.3%), and T2 hyperintensity in 107 (13.8%). The accuracy and sensitivity of HCC diagnosis was improved signi cantly after adding at least one ancillary feature compared with enhancement patternbased diagnosis of HCCs (79.9% vs. 91.1% for accuracy, p<.0001 and 79.1% vs. 92.0% for sensitivity, p<.0001) with a minor tradeoff in speci city (87.8% vs. 82.4%, p = .125). Adding at least two ancillary features improved accuracy (88.1%, p<.0001) and sensitivity (88.1%, p<.0001) without changing speci city (87.8%, p=1.0). Conclusion: Adding intratumoral ancillary features to enhancement patterns on gadoxetic acid-enhanced MRI improved accuracy and sensitivity, while maintaining speci city for HCC diagnosis. SS 2.6 Differentiating malignant from benign hyperintense nodule on unenhanced T1-weighted images in patients with chronic liver disease: value of gadoxetic acidenhanced and diffusion-weighted MR imaging J.Y. Moon1, S.H. Kim1, S.-Y. Choi2, J. Lee3; 1Seoul/KR, 2Bucheon/KR, 3Cheongju-si/KR Purpose: To evaluate the value of gadoxetic acid-enhanced and diffusionweighted (DW) MR imaging for distinguishing malignant from benign hyperintense nodules on unenhanced T1-weighted images (T1WIs) in patients with chronic liver disease. Material and methods: Forty-two patients with 37 malignant and 41 benign hyperintense nodules on unenhanced T1WIs who underwent gadoxetic acidenhanced and DW MR imaging, followed by histopathological examination, were included. Qualitative (signal intensity [SI], arterial enhancement, washout) and quantitative (size, contrast enhancement index, tumor-to-liver SI ratio, mean and minimum apparent diffusion coef cient [ADCmean and ADCmin] values) analyses were conducted by two radiologists in consensus. Signi cant imaging  ndings on univariate and multivariate analyses were identi ed and their diagnostic performances were analyzed for predicting malignant hyperintense nodules. Results: In univariate and multivariate analyses of qualitative and quantitative variables, hyperintensity on T2WI (OR, 13.58; P = 0.02), arterial enhancement (OR, 8.21; P = 0.002), ADCmin ≤ 0.83 x 10-3mm2/s (OR, 6.88; P = 0.008) were independently signi cant factors for differentiating malignant from benign hyperintense nodules. When two of these three criteria were combined, 75.7% (28/37) of malignant nodules were identi ed with a speci city of 92.7%, and all three criteria were satis ed, the speci city was 97.6%. Conclusion: Gadoxetic acid-enhanced and DW MR imaging may be helpful for differentiating malignant from benign hyperintense nodules on unenhanced T1WI. SS 2.7 Comparison of the accuracy of AASLD and LI-RADS criteria for the non-invasive diagnosis of small HCC O. Fouque1, M. Ronot1, M. Esvan2, J. Lebigot3, C. Aubé3, V. Vilgrain1; 1Clichy/FR, 2Paris/FR, 3Angers/FR Purpose: To prospectively compare the diagnostic accuracy of the AASLD and LI-RADS criteria for the non-invasive diagnosis of small HCC. Material and methods: Between April 2009 and April 2012, patients with cirrhosis and one to three 10-30 mm nodules were enrolled and underwent CT and MR imaging. The diagnostic accuracy of the combination of the AASLD and the LI-RADS criteria were determined based on their sensitivity, speci city, positive (PPV) and negative predictive values (NPV) with 95% con dence intervals. Results: 595 nodules were included (559 [341 HCC, 61%] with MRI and 529 [332 HCC, 63%] with CT). 0% LR1-LR2, 33% and 41% LR3, 65% and 70% LR4, 94% and 96% LR5 and 67% and 82% LR5V were HCC on MRI and CT, respectively. The sensitivity/speci city/PPV/NPV of the AASLD criteria were 72.5% 87.6% 90.2% and 66.9% for MRI, and 71.4%, 77.7%, 84.3%, and 61.7% for CT. For LR5V+LR5 they were 58.2%, 93.6%, 93.4% and 58.7% on MRI and 44.9%, 95.9%, 94.9%,and 50.8% on CT. For LR5V+LR5+LR4 they were 87.1%, 69.1%, 81.6%, and 77.3% on MRI and 85.8%, 66%, 81% and 73.5% on CT. Conclusion: The current version of the LI-RADS is not more accurate than the AASLD score for the non-invasive diagnosis of small HCC in high-risk patients but it provides important information on the probability of having HCC in highrisk patients allowing possible changes in management in these patients. SS 2.8 Differentiating hypervascular hyperplastic nodule from hypervascular hepatocellular carcinoma in patients with alcoholic liver cirrhosis: value of gadoxetic acidenhanced and diffusion-weighted MR imaging S.S. Kim1, S.H. Kim2, K.D. Song2; 1Cheonan-si, Chungcheongnam-do/KR, 2Seoul/KR Purpose: To evaluate the value of gadoxetic acid-enhanced and diffusionweighted (DW) magnetic resonance (MR) imaging for differentiating hypervascular hyperplastic nodule (HHN) from hypervascular hepatocellular carcinoma (HCC) in patients with alcoholic liver cirrhosis (LC). Material and methods: Among 310 patients with alcoholic LC who underwent gadoxetic acid-enhanced and DW MR imaging, 11 patients with 65 HHNs and 23 patients with 32 hypervascular HCCs were included. Qualitative and quantitative analyses were conducted. Signi cant MR imaging  ndings on univariate and multivariate analyses were assessed and their diagnostic performances for predicting HHN were analyzed. Results: In univariate and multivariate analysis, lesion size (≤14 mm) (odds ratio [OR] = 145.65) and high SI on unenhanced T1-weighted image (T1WI) (OR = 59.18) were independently signi cant imaging  ndings for predicting HHN (P < 0.001 and P = 0.001, respectively). The speci city of their combination for predicting HHNs was 100%. In quantitative analysis, mean SI on HBP image and lesion-to-liver SI ratio on HBP of HHNs were signi cantly higher than those of hypervascular HCCs (P < 0.001, respectively). Mean ADC values and lesion-to-liver ADC ratios between HHNs and HCCs were not signi cantly different (P = 0.163 and P = 0.531, respectively). Conclusion: Gadoxetic acid-enhanced and DW MR imaging may be helpful for differentiating HHN from hypervascular HCC in patients with alcoholic LC and lesion size ≤ 14mm and high SI on unenhanced-T1WI were signi cant imaging  ndings for predicting HHN. SS 2.9 The value of gadoxetic acid-enhanced and diffusionweighted MR imaging for differentiating hepatocellular adenoma from hepatocellular carcinoma J. Lee1, S.H. Kim2, J.Y. Moon2; 1Cheongju/KR, 2Seoul/KR Purpose: To evaluate the value of gadoxetic acid-enhanced and diffusionweighted (DW) magnetic resonance (MR) imaging for differentiating hepatocellular adenoma (HCA) from hepatocellular carcinoma (HCC). Material and methods: This study had institutional review board approval; the requirement for informed consent was waived. One hundred and thirty-seven patients with 143 lesions (45 HCAs and 98 HCCs) were included in the study. There were 37 female patients and 100 male patients (mean age, 58 years). Two radiologists evaluated morphologic features, signal intensity (SI) of tumors on MR images including DW (b=800) imaging and dynamic enhancement pattern in consensus. For quantitative analysis, tumor-to-liver SI ratio and contrast enhancement index (CEI) on unenhanced, dynamic, and hepatobiliary phase images and apparent diffusion coef cient (ADC) maps were calculated. Statistically signi cant imaging  ndings were identi ed through univariate and multivariate analyses, and their diagnostic performance for predicting HCA was analyzed. Results: In univariate and multivariate analyses, high SI on portal phase images (p=0.0009), lower tumor-to-liver SI ratio on T2-weighted images (<1.647, p=0.0009), and higher tumor-to-liver SI ratio on T1-weighted images (≥0.807, p=0.0068) and tumor-to-liver SI ratio on ADC maps (≥0.841, p<0.001) were independently signi cant factors for predicting HCA. When three of these four criteria were combined, 68.9% (31/45) of HCA were identi ed with speci city of 92.9%. When all four criteria were satis ed, speci city was 100%. Conclusion: Gadoxetic acid-enhanced and DW MR imaging may be helpful for differentiating HCA from HCC. SS 2.10 Comprasion of intravoxel incoherent motion and conventional-diffusion weighted imaging parameters for hepatacellular carcinoma grading at explant B.K. Sokmen, A. Oz, S. Server, M. Dayangac, N. Inan, G. Bulbul Dogusoy, C. Balci; Istanbul/TR Purpose: To compare the diagnostic value of IVIM and conventional DWI parameters for estimation the HCC grading in explant livers. Material and methods: Twenty-three patients with histopathologically diagnosed HCC at explant were included in this retrospective study. All patients were examined by 1.5T MRI within 90 days before liver transplant. IVIM (16 different b factors of 0-1300 s/mm2) and conventional DWI were obtained. Two different ADC maps reconstructed from conventional DWI (ADCcon) and IVIM (ADCivim). The mean D, D* and f values also calculated from IVIM. Histopathologically, HCC was classi ed as low (grade 1, 2) and high (grade 3, 4) grade. Quantitatively, ADCcon, ADCivim, D, D* and f values were compared by student’s t test. The relationship between the parameters and grade was analyzed by Spearman correlation test. To evaluate the diagnostic performance of the parameters, ROC analysis was performed. Results: The ADCcon and ADCivim values of high-grade HCCs were signi cantly lower than those of low grade ones (p<0.005, respectively). Both ADCcon and ADCivim values were inversely correlated with grade (r=-519, p=0.011; r=-421, p=0,046, respectively). The f value of the high-grade HCC was signi cantly higher than low grade (p=0.005). The f values were positive correlated with grade (r=0.548, p=0.007). The best discriminative parameter was the f value (mean f value was 26% for low grade, 38% for high grade). Conclusion: Conventional DWI and IVIM parameters, especially f values, may help in differentiating low and high-grade HCC. Conference Suite II MC 3 Scienti c Session SS 3 Rectal cancer imaging: pre and post treatment evaluation SS 3.1 Restaging after CRT for rectal cancer: how can we better select the ypT0N0 patients for organ preservation? M. Maas1, M. Van Der Sande1, B. Hupkens2, M.H. Martens3, D.M.J. Lambregts1, F.C.H. Bakers2, R.G.H. Beets-Tan1, S. Breukink2, G.L. Beets1; 1Amsterdam/NL, 2Maastricht/NL, 3Sittard/NL Purpose: To identify factors that might improve the selection of patients with ypT0(N0) after CRT by reassessing imaging in missed pathologic complete responders after surgery. Material and methods: 42 patients with ypT0 after surgery were identi ed. MRI+DWI+endoscopy were re-evaluated by an expert radiologist and expert surgeon, who scored a con dence level for likelihood of CR and residual N+ disease and described the morphology/aspect of MRI & endoscopy after CRT. Updated selection criteria for CR were used. Two groups were formed based on the re-evaluation of images: (1) residual tumour at reassessment (non-CR) and (2) (near) CR. Results: 33 patients had ypT0N0, the remaining 9 had ypT0N+. Main reasons for missing CR were heterogeneous T2-signal, residual focal/massive diffusion-restriction, ycN+ disease and mucosal abnormalities at endoscopy. These imaging factors were signi cantly more frequently found in patients who were still deemed to have residual tumour compared to those who were deemed a CR upon reassessment. 8 patients were overstaged as ycN+, of which 7 had irregular nodes. Also, nodal irregularity was found in 6/9 patients with ypN+ disease. Normalized nodes all were ypN0. Conclusion: Missing a CR after CRT is usually due to heterogeneous T2-signal, extensive  brosis, residual diffusion-restriction, ycN+ disease and residual mucosal abnormalities. Nodes are overstaged in approximately half of the cases. Awareness of these pitfalls can help in the selection of patients for a watch-and-wait strategy after CRT for rectal cancer. SS 3.2 Rectal cancer: comparison of MR-TRG, volume ratio and signal intensity decrease for the identification of complete responders after radiochemotherapy S. Picchia1, M. Rengo2, D. Caruso1, D. Bellini1, D. De Santis1, A. Laghi1; 1Latina/IT, 2Rome/IT Purpose: To compare three methods to identify complete responders after chemoradiotherapy (CRT) in a population of patients with locally advanced rectal cancer. Material and methods: 65 patients, diagnosed with locally advanced rectal cancer were prospectively enrolled in the study. All patients underwent MRI on a 3-Tesla before, during and after CRT. All patients underwent total mesorectal excision (TME). MR-TRG, volume reduction ratio (VR) and signal intensity percentage decrease (SI) were compared. Measurements were performed on the entire tumour volume using a dedicated software. MR-TRG, VR and SI were compared with histology. DFS, OS and ROC analysis were evaluated and compared among the three groups. Patients were strati ed according to the histology result in complete responders (CR) and partial or non-responders (PNR). Results: MR-TRG and VR were signi cantly different in CR and PNR patients (P=0,0005) while no signi cant differences were observed for SI (p=0.14). Signi cantly higher sensitivity and speci city were observed for MR-TRG compared to VR and SI (p=0.001). MR-TRG was also more accurate to predict the OS and DFS (p=0.002). Conclusion: MR-TRG is more accurate than VR and SI for the identi cation of CR and correlates with patients’ survival. SS 3.3 DCE-MRI shows slower flow and more homogeneous vascularity in responding tumours after CRT for rectal cancer R.A.P. Dijkhoff1, M. Maas1, G. Shakirin2, D.M.J. Lambregts1, J.J.M. Van Griethuysen1, M. Weibrecht2, M. Perkuhn2, M.C. De Boer1, R.G.H. Beets-Tan1; 1Amsterdam/NL, 2Aachen/DE Purpose: To evaluate whether semiquantitative parameters derived from prechemoradiation (pre-CRT) DCE-MRI predicts response to chemoradiation (CRT). Material and methods: 20 patients with primary locally advanced rectal cancer underwent DCE-MRI with the contrast agent gadofosveset-trisodium preCRT. DCE-MRI was processed with the Intellispace Discovery research platform (Philips Healthcare). One reader delineated whole-tumour volumes on DWI. Semi-quantitative DCE-parameters based on the enhancement curve (AUC(60), (AUC of time to peak (TTP), maximum enhancement, bolus arrival time (BAT), initial signal excess (ISE), mean transit time (MTT), wash-in&washout parameters) were compared between patients with complete (CR;ypT0) or good response (GR;ypT0-2) and non-responders. Additionally, heterogeneity of DCE parameters (measured by coef cient of variance (CoV:sd/mean)) was compared. Results: 8/20 (40%) had CR. Almost all DCE-parameters were lower in CR&GR (p>0.05). MTT and BAT were higher in CR, with BAT signi cantly higher (p=0.015). In GR the BAT was also signi cantly higher (p=0.028). Heterogeneity was higher in CR for almost all DCE-parameters, except for BAT and washout, which were lower in CR (p>0.05). In GR AUC60 and TTP were signi cantly more heterogeneous than in poor responders (p=0.024-0.041), while BAT was signi cantly less heterogeneous in GR. Conclusion: Bolus arrival time is longer and less heterogeneous in complete & good responders to CRT, potentially re®ecting slower but more homogeneous ®ow. This could represent longer exposure to chemotherapy and reduced hypoxia and thus higher response. Most DCE parameters were lower in responders re®ecting lower angiogenetic activity. SS 3.4 Experience of the MRI tumour-regression-grading (TRG) system for anal cancer: interobserver agreement and impact of diffusion-weighted imaging D. Prezzi1, S. Gourtsoyianni1, K. Owczarczyk1, A. Gaya1, M. Leslie1, A. Qureshi1, R. Glynne-Jones2, V. Goh1; 1London/GB, 2Northwood/GB Purpose: To evaluate independently a recently proposed MRI TRG system for anal cancer post chemoradiation. To assess interobserver agreement based on multiplanar high-resolution T2-weighted (T2-w) imaging. To measure the impact of additional diffusion-weighted imaging (DWI) on TRG scores and interobserver agreement. Material and methods: Forty-three patients with biopsy-proven anal squamous-cell-carcinoma (ASCC) underwent staging pelvic MRI at baseline and 3-6 months after chemoradiation, including multiplanar high-resolution T2weighted sequences and DWI (b=0;800 s/mm2). Two radiologists scored posttreatment scans independently in two separate sessions:  rst using high-resolution T2-w sequences; a month later, combining T2-w with DWI. Upon statistical advice, interobserver agreement weighted-Kappa was calculated. Results: No cases were assigned an initial TRG score of ‘1’ or ‘5’. TRG scores of ‘2’ (excellent response with  brosis) or ‘3’ (indeterminate response with heterogeneous signal at the tumour site) accounted for most cases (39 cases/43) and determined substantial interobserver discordance based on T2-w sequences alone (15 cases/39). Interobserver agreement improved from ‘fair’ [Kappa=0.36] to ‘moderate’ [Kappa=0.55] with the inclusion of DWI; 6 cases of discordant-indeterminate response (TRG ‘2/3’) resolved in favour of excellent response (TRG ‘2’). Conclusion: A 5-category TRG system may be redundant in ASCC. Interobserver agreement in this independent cohort is lower than previously reported, possibly due to misinterpretation of category descriptors. DWI appears valuable for staging ASCC post-chemoradiation. SS 3.5 MR T2 mapping imaging for quantitatively evaluating tumor response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer F. Li, Z. Zhou, W. Cao, Z. Li, J. Zhou, R. Malla, A. Mohamoud, X. Wang, J. Gong; Guangzhou/CN Purpose: To explore the potential value of MR T2 mapping imaging in evaluating the response to neoadjuvant chemoradiotherapy (CRT) in locally advanced rectal cancer. Material and methods: 36 patients with locally advanced rectal cancer underwent MRI before and after CRT. MRI protocols included axial FSE T2 weighted imaging and T2 mapping imaging. The whole tumor tissue on T2 maps was included by manually drawing the region of interests (ROIs). T2 values before and after CRT were measured. T2 changes (ΔT2), T2 reduction rate before and after CRT were calculated, respectively. Patients were divided into good response (GR) group and poor response (PR) group according to the tumor regression grade. Parameters were compared by using independent-samples T test. Receiver operating characteristic curve (ROC) and the corresponding areas under the ROC curve (AUC), accuracy, sensitivity, speci city, positive predictive value (PPV) and negative predictive value (NPV) were computed to assess the diagnostic performance of ΔT2 and T2 reduction rate. Results: 26 patients were classi ed as GR and 10 patients had a PR. ΔT2 and T2 reduction rates were signi cantly different (P<0.05) between GR and PR group. ΔT2 and T2 reduction rate had a AUC of 0.95 and 0.96, PPV of both 93% for the GR, respectively, and with a NPV of both ΔT2 and T2 reduction rate were 89% for the GR, respectively. Conclusion: High ΔT2 and T2 reduction rate correspond to pathological good response. SS 3.6 DCE-MRI has a value in predicting and assessing response to chemoradiation for rectal cancer R.A.P. Dijkhoff, R.G.H. Beets-Tan, D.M.J. Lambregts, G.L. Beets, M. Maas; Amsterdam/NL Purpose: To perform a systematic review evaluating the clinical value of DCEMRI in rectal cancer. Material and methods: A search was performed on Pubmed, Embase and the Cochrane library. Studies on DCE-MRI for tumour aggressiveness and primary (re)staging after chemoradiation (CRT) were included. Information on population, DCE-technique, DCE-parameters and outcome were extracted. Results: 19 studies were identi ed; 10 evaluated quantitative analyses, 6 semiquantitative analyses and 3 evaluated both. 8 studies evaluated correlation between DCE-parameters and angiogenesis or tumour aggressiveness. 11 evaluated response prediction pre- and post-CRT. Several semiquantitative parameters showed a signi cantly positive correlation with angiogenesis (mostly wash-in parameters), for quantitative analyses con®icting results were found. Con®icting results were also reported for the correlation between DCEparameters and tumour aggressiveness. Both higher and lower vascularity in more aggressive tumours are reported, while some studies report no correlation. Six studies showed a predictive value of Ktrans for response. Higher Ktrans pre-CRT was signi cantly correlated with a complete/good response, but reported pre-CRT Ktrans varied substantially (0.36-1.93). Post-CRT reduction in Ktrans of 32%-36% was signi cantly associated with response. For semiquantitative analyses pre-CRT late-slope was reported to be signi cantly lower in good responders, however, only few studies exist on semiquantitative analyses of post-CRT DCE-MRI. Conclusion: DCE-MRI in rectal cancer is promising for response prediction and assessment of CRT, where a high pre-CRT Ktrans and a decrease in Ktrans are signi cantly predictive for response. SS 3.7 MRI of rectal cancer response to therapy: comparison of DWI and ADC between 3T and 1.5T M. Zerunian, D. Caruso, M. Rengo, D. Bellini, T. Biondi, A. Laghi; Latina/IT Purpose: To compare DWI and ADC values between 3T and 1.5T MRI of rectal cancer pre, during and post-therapy. Material and methods: This study is part of larger study founded by AIRC (Associazione Italiana Ricerca contro il cancro). 22 consecutive patients with locally advanced rectal cancer were prospectively analyzed on both 3T and 1.5T MR. All patients underwent a neoadjuvant chemoradiotherapy (CRT) and DWI and ADC values were analyzed pre, during and post-CRT. A region of interest was drawn in the area where the tumor was well detectable and signal intensity was calculated on DWI and ADC maps. Two readers with different experience in assessing rectal cancer MRI evaluated the images, blinded for histological results. Results: Signi cant differences were observed for DWI on 3T compared to 1.5T for pre-CRT (324.37±172.2 vs. 70.72±20.8; p<0.05), during CRT (199.86±128.08 vs. 52.59±17.16; p<0.05) and post-CRT (135.53±68.03 vs. 43.17±14.47; p<0.05), while no signi cant differences were reported for ADC values between 3T and 1.5T for pre-CRT (0.85±0.21 vs. 0.83±0.19), during CRT (1.11±0.25 vs. 1.18±0.33) and post-CRT (1.24±0.36 vs. 1.27±0.35), respectively (all p>0.05). A progressive decreasing trend for DWI was observed during the three controls, while an increasing trend was noticed for ADC in the three examinations, both for 3T and 1.5T. Conclusion: DWI values were signi cantly higher on 3T than 1.5T while no signi cant differences were observed on ADC map. SS 3.8 Fully automated segmentation of rectal tumours on MRI using supervised learning techniques with expert-reader input S. Trebeschi1, J.J.M. Van Griethuysen1, H.J.W.L. Aerts2, D.M.J. Lambregts1, M.J. Lahaye1, F.C.H. Bakers3, N. Peters4, M. Verheij1, R.G.H. Beets-Tan1; 1Amsterdam/NL, 2Boston, MA/US, 3Maastricht/NL, 4Heerlen/NL Purpose: To perform fully automated segmentation of locally advanced rectal carcinomas (LARCs) via a supervised learning technique (SLT) trained and validated using delineations by expert-readers. Material and methods: We selected the MRI scans (1.5T, T2-weighted and b1000 DWI) of 140 LARC-patients. Manual whole tumor volume delineation, performed by an expert radiologist (on b1000 DWI, was used as the standard reference. From each image, 500 pixels within the tumor and 500 pixels outside the tumourr were randomly sampled. For each pixel, we extracted the surrounding patch of 25x25 in all MRI sequences, resulting in 1000 patches per patient. By  tting the resulting three patches as color channels, a multiparametric representation of the image was obtained. The architecture consisted of three convolutional layers. A fully connected layer of 256 neurons was placed between the convolutional layers and the output layer. Both classes were balanced due to randomized sampling procedure. Patients were randomly and equally divided between training and testing. Results: The algorithm was trained until it reached a stable condition. The trained algorithm was then applied on the test set, reaching an AUC of 0.94 based on the probability of being tumor for each pixel. Conclusion: Automatic segmentation using an SLT is able to reproduce manual expert segmentations with an AUC of >0.90, suggesting that it can be a time-ef cient solution to help delineation in daily practice. Purpose: To investigate the magnetic resonance (MR) characteristics of primary rectal signet ring cell carcinoma (SRCC), compared with conventional rectal adenocarcinoma (AC). Material and methods: 28 cases of rectal SRCC and 31 cases of AC con rmed by pathology with primary rectal MR data were retrospectively analyzed. Compare SRCC with AC about the TNM stage, the basic imaging characteristics and tumor signal from T2WI sequence. Results: The distant metastasis rate of SRCC was 25% (7/28), 10.7% (3/28) in peritoneal metastasis. The ratio of SRCC circumferential in ltration (>1/2 of the periphery) was higher than that of AC, 92.9% (26/28) vs. 61.3% (19/31), p=0.004. The tumor/fat, tumor/muscle and tumor/urine signal ratios of SRCC from T2WI sequence were higher than that of AC. There were no signi cant differences in the transverse maximum thickness, longitudinal diameter, and the distance the lower edge of the tumor from anal edge between SRCC and AC. In terms of the distance tumor breakthrough from the intrinsic muscle layer of the rectum, AC was higher than SRCC (6.03 mm vs. 4.03 mm, P=0.044). Conclusion: The rectum invasion circumferential diameter range of SRCC was larger than rectal conventional adenocarcinoma, but the breakthrough of muscular layer distance was relatively limited. The MR T2WI signal of rectal SRCC was often higher than that of conventional adenocarcinoma, which may provide a certain prediction basis for rectal cancer multidisciplinary therapy. SS 3.10 Air artefacts on diffusion-weighted MRI of the rectum: effect of applying a rectal micro-enema J.J.M. Van Griethuysen1, E.M. Bus1, M. Hauptmann1, M.J. Lahaye1, M. Maas1, G.L. Beets1, F.C.H. Bakers2, R.G.H. Beets-Tan1, D.M.J. Lambregts1; 1Amsterdam/NL, 2Maastricht/NL Purpose: Diffusion-weighted imaging (DWI) using single-shot echo planar imaging (EPI) is increasingly included in standard rectal MRI-protocols. EPI-DWI is prone to susceptibility artefacts, mainly caused by air in the rectal lumen. Aim was to assess whether application of a micro-enema can reduce these artefacts. Material and methods: 50 patients were included who each underwent multiple sequential DWI-MRIs (1.5T; highest b-value b1000) during follow-up for a wait-and-see approach after chemoradiotherapy. Until March 2014 DWI-MRIs were acquired without bowel preparation, thereafter a micro-enema (Microlax®;5 ml) was routinely applied shortly prior to acquisition. Two readers scored the presence/severity of air artefacts per scan, ranging from 0 (no artefact) to 5 (severe artefact). A score >= 3 (moderate-severe) was considered a clinically signi cant artefact. Scores were compared between DWI-scans with/without a micro-enema. Potential confounding factors (age/gender, acquisition parameters, MRI-hardware, endoscopy prior to MRI) were taken into account. Results: In total 335 DWI-MRIs were assessed. Signi cant air artefacts were seen in 24.3% (no micro-enema) vs. 3.7% (with micro-enema). Using binary logistic regression with samples clustered by patient, the odds ratio between the use of a micro-enema and presence of signi cant artifacts was 0.12 (95% CI 0.04-0.40), p = 0.0005. None of the assessed potential confounders signi cantly altered this effect. Conclusion: The use of a micro-enema prior to rectal EPI-DWI examinations signi cantly reduces air artefacts, compared to examinations without bowel preparation. Conference Suite II MC 3.2 Scienti c Session SS 4 Diffuse and chronic liver diseases SS 4.1 Prospective comparison of shear-wave elastography, cap and conventional ultrasound for non-invasive detection and grading of steatosis M. Ronot, P.-E. Rautou, M. Dioguardi Burgio, L. Castera, V. Vilgrain; Clichy/FR Purpose: To prospectively compare the performance of ultrasound (US), controlled attenuation parameter (CAP), ultrasound beam attenuation (UBA), and speed of sound (SOS) derived form shear-wave elastography for diagnosing and grading steatosis, taking liver biopsy (LB) as a reference. Material and methods: 296 patients (62% male, mean 50±14 yrs) underwent LB. Data of US performed before referral (routine-US, n=267), US performed just before LB (expert-US; n=288), CAP (n=256), UBA (n=133), and SOS (n=155) performed at the time of LB were prospectively collected. Steatosis was graded on LB as S0 (<5%), S1 (5-33%), S2 (33-66%) and S3 (>66%). Results: Steatosis was grade S0, S1, S2 and S3 in 189 (64%), 65 (22%), 28 (9%), and 14 (5%) patients. AUROCs for detection of any steatosis ranged between 0.60±0.05 and 0.71±0.03, without difference between techniques. For the identi cation of S2-3, expert-US and CAP showed the highest performance (AUROC 0.84±0.04 and 0.88±0.04). For detection of S3, CAP outperformed other techniques with 92% patients correctly classi ed. Combining expert-US and CAP (n=249) correctly classi ed 191 (77%), 226 (91%) and 242 (97%) for the detection of any grade, S2, and S3 when both parameters were positive. Conclusion: The ability of novel SWE derived techniques (UBA and SOS) to detect steatosis is limited and not better than US performed by an expert radiologist. For severe steatosis, CAP performs better than other technics. Combining US with CAP improves the proportion of well-classi ed patients. SS 4.2 2D shear wave liver elastography using comb-push excitation technique: changes of elasticity value per the size of region of interest J.Y. Lee, D.H. Park, J.K. Han; Seoul/KR Purpose: The aim of this study was to investigate if there is a signi cant difference in elasticity value according to the size of region-of-interest (ROI) on 2D shear wave liver elastography using comb-push excitation technique and time-interleaved. Material and methods: 101 patients who underwent liver stiffness measurement using two different ROIs (small ROI vs. large ROI) on the 2D shear wave elastography were retrospectively included in this study. Among them, 25 patients underwent transient elastography. Statistical analysis using paired t-test and Pearson correlation coef cient was performed. Results: Mean elasticity value of small ROI measurement (5.64 ± 2.57 kPa) was signi cantly lower than that of large ROI measurement (6.58 ± 2.57 kPa) (P < 0.0001). Comparing transient elastography, small ROI measurement showed higher correlation coef cient (r= 0.771; CI 0.551 to 0.897) with transient elastography than did large ROI measurement (r=0.689; CI 0.404 to 0.852). Conclusion: According to the size of ROI, 2D shear wave elastography using comb-push technique showed signi cantly different elasticity values. The size of ROI should be addressed and standardized in future research using this technique. SS 4.3 Two-dimensional shear-wave elastography performance in the noninvasive evaluation of liver fibrosis using a newer shear-wave technology C.L. Silva, L.S.A. Guimarães, V.F.A. Borges; Uberlândia/BR Purpose: Staging liver  brosis is necessary to de ne therapeutic management of chronic hepatitis C virus (HCV). The new “gold standard” is transient elastography (TE), used to replace liver biopsy. Newer 2D-shear-wave (2D-SW) tecnologies have been developed but have yet to be validated. The purpose is to evaluate the reliability of the 2D-SWE technique in staging of  brosis in HCV using TE as the gold standard. Material and methods: A cross-sectional study of patients with HCV, evaluated on the same date by TE and 2D-SW, was performed by a single operator, using Fibroscan (Echosens) and LogiqE9 with 2D-SW (GE Healthcare). Ten valid measurements were obtained for both techniques and the median result in kPa was used for the statistical analysis, with cut-offs established by each manufacturer and METAVIR classi cation for correlation between the two methods. The measurement obtained from 2D-SW were correlaterd with the TE-derived stages of  brosis. Results: 107 patients were evaluated. There was a signi cant correlation between TE and 2D-SWE measurements (r=0.80, p=0.01). The mean elasticity values using 2D-SW for each METAVIR stage was: FO/F1 (n = 65: 6.0 +/- 1.3 kPa). F>=2 (n = 16: 8.3 +/- 0.35 kPa), F>=3 (n = 13: 10.19 +/- 0.32 kPa) and F4 (n = 13: 13.57 +/- 1.30 kPa). Conclusion: This new 2D-SW liver elastography showed good agreement with TE results, and it can be used in clinical practice for staging  brosis. SS 4.4 Skin-liver distance and interquartile-median ratio as determinants of inter-operator concordance in acoustic radiation force impulse (ARFI) imaging S. Su, W. Wang, D. Nadebaum, A. Nicoll, S. Sood, A. Gorelik, J. Lai, R. Gibson; Melbourne, VIC/AU Purpose: The accuracy of ARFI ultrasound compared to liver biopsy is higher when there is concordance between F-scores of two or more operators. We hypothesised that when the  rst operator interquartile range/median-velocity ratio (IMR) is <0.3 and skin-liver distance (SLD) is ≤2.5cm, there is greater interoperator concordance and a second operator is not necessary. Material and methods: Two-operator ARFI ultrasound (Siemens S2000) measurements (F-score, SLD and IMR) were recorded for 927 consecutive patients. Concordance was de ned as F-scores in same or adjacent stages. Chisquared testing (SPSSv17) compared concordance for SLD≤2.5 cm versus SLD>2.5 cm; and IMR <0.3 versus IMR≥0.3 when SLD≤2.5cm, in each of the F-score groups of 0/1, 2, 3 and 4. Results: Statistically signi cant differences were demonstrated between SLD≤2.5cm and SLD>2.5cm groups when F-score was 0/1 or 4 (p=0.005), and when F-score was 2 or 3 (p<0.0005). Concordance, when SLD≤2.5cm, was more than 85% for all F-score groups. Chi-squared tests comparing higher skin-liver distances were not performed as correlation with biopsy reduces when SLD>2.5cm. In the SLD≤2.5cm group, concordance fell below 85% when IMR≥0.3, for all F-scores except F2. Speci cally, p-values comparing IMR<0.3 and IMR≥0.3 in the various  rst operator F-score groups were p=0.040 for F0/1, p=0.580 for F2, p=0.342 for F3, and p<0.0005 for F4. Conclusion: ARFI measurements from one operator can be considered acceptable when SLD≤2.5cm and IMR<0.3. Otherwise, adding a second operator can improve con dence in the result. SS 4.5 Liver iron concentration in metabolic syndrome with hyperferritinemia (dysmetabolic hyperferritinemia): results from a prospective cohort of 312 patients J.M. Alústiza1, A. Ugarte Nuño1, I. Urreta1, E. Salvador1, J.I. Emparanza1, E.M. Zapata,2, L. Zubiaurre2, A. Iribarren2, A. Castiella2; 1San Sebastián/ES, 2Mendaro/ES Purpose: Aproximately 25% of adult population in western countries have metabolic syndrome (MS). Hyperferritinemia (HF) is frequently present in patients with MS, called dysmetabolic hyperferritinemia. It has been publised that HF is associated with iron overload in these patients, but some doubts persist about it. Purpose: to study liver iron concentration (LIC) in patients referred for hyperferritinemia to six different hospitals in the Basque Country (multicenter study), Spain, and determine if there are differences between patients with or without MS. Material and methods: Prospective study of 312 consecutive patients with HF (>200 mg/L women, >300 mg/L men), conducted from December 2010 to April 2013. LIC was determined by MRI (previously validated SIR method. Alustiza JM, et al. Radiology 2004). Results: 276 of 312 patients were evaluable. 135 patients (48.9%) presented MS. MS group (n=135): mean LIC was 30.83±19.38 μmol/g (women) and 38.84±25.50 μmol/g (men), with 37.66±24.79  μmol/g  (CI 95%; 33,44 to 41,88)  for the whole group. Non-MS group (n=141): mean LIC was 34.88±16.18  μmol/g (women), and 44.48±38.16 μmol/g (men), with 43.39±36.43(IC 95%, 37,32 to 49,46) for the whole group. We compare the mean values of LIC from both groups (MS vs NMS) by Pearson’s Chisquare test and Fisher’s exact test: no signi cant differences were seen (p = 0.12). Conclusion: Patients with HF and MS (dysmetabolic hyperferritinemia) present a mean LIC near normal values and their values do not differ from those of patients with HF and without MS. SS 4.6 Preperitoneal fat area as a potential noninvasive marker of increased risk of severe non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes D.B. Parente1, J.A. Oliveira Neto1, P.E.A.A. Brasil1, F.F. Paiva2, J.P.R. Ravani1, M.B. Gomes1, V. Lanzoni3, C.F.F. Campos1, L. Machado-Silva1, R.M. Perez1, R.S. Rodrigues1; 1Rio de Janeiro/BR, 2São Carlos/BR, 3São Paulo/BR Purpose: Fat distribution may have prognostic value in the evaluation of nonalcoholic fatty liver disease. This study was conducted to evaluate associations of MRI-measured abdominal fat areas with steatosis, steatohepatitis, and  brosis, assessed histopathologically, in patients with type 2 diabetes. Material and methods: This prospective study included 66 patients with type 2 diabetes (12 males, 54 females, age 26–68 years), without chronic liver disease of other causes. Axial dual-echo MR images were acquired. Visceral, subcutaneous, and preperitoneal fat areas were measured using Osirix software. Liver biopsy specimens were obtained from all patients and examined histopathologically to evaluate steatosis, steatohepatitis, and  brosis. Linear (for steatosis) and logistic (for steatohepatitis and  brosis) regression models were  tted for the outcomes. R2 was used as a measure of how much model variance the predictors explained, and to compare different predictors of the same outcome. Results: Visceral and preperitoneal fat areas correlated well with histopathologically determined liver steatosis grade (both p = 0.004) and liver  brosis ( p = 0.008 and  p  = 0.037, respectively). All fat areas correlated well with steatohepatitis (p ≤ 0.002). Preperitoneal and visceral fat areas were the best predictors of steatohepatitis (R2 = 0.379) and  brosis (R2 = 0.181), respectively. Conclusion: Preperitoneal fat area was the best predictor of steatohepatitis and is a potential new noninvasive marker for use in the screening of these patients to detect more aggressive forms of NAFLD. SS 4.7 Case series of Wilson’s disease: are there specific multiparametric liver ultrasound findings? L. Skrule, M. Radzina, A. Zarina, I. Tolmane; Riga/LV Purpose: To evaluate the current liver ultrasound  ndings in patients with Wilson’s disease (WD) in correlation with clinical-laboratory data. Material and methods: In a case series we have analysed 11 diagnosed cases of WD patients, evaluating for multiparametric ultrasound (US)  ndings: baseline US, point shear wave elastography (pSWE) and contrast-enhanced ultrasonography (CEUS) of liver in correlation with clinical and laboratory  ndings. Results: There were genetically proved 11 patients, 8 of them had non-differentiated liver disease in history. Baseline ultrasound revealed diffuse parenchymal changes with increased echogenicity (n=7), coarse-grained texture (n=6), multiple hypoechogenic nodules (n=3), liver contour irregularity suggesting cirrhosis (n=4) and perihepatic fat thickening (n=3). Non-speci c contrast enhancement (n=3) and nodular lesions with late washout (n=2) was proved by CEUS. Fibrosis was detected by pSWE measurements (F1 (n=2), F4 (n=1)). Decreased plasmatic ceruloplasmine (n=5) levels were associated with nodular liver changes on US and Kayser–Fleischer rings (n=3).All patients had elevated copper level in 24h urine sample, however liver functional analysis did not correlate with structural changes. Conclusion: There are some speci c  ndings: hypoechoic nodules and perihepatic fat thickening in liver US and nodularity on CEUS with late wash-out pattern with variable  brosis grade on elastography, that can indicate possible Wilson’s disease. Multiparametric ultrasound can be used as  rst modality to assess liver involvement as well as during progression of the Wilson’s disease. SS 4.8 The usefulness of native T1 of the liver obtained by SMART1Map (saturation method using adaptive recovery times for cardiac T1 mapping) in the evaluation of the severity of the chronic liver diseases T. Nonaka1, A. Yamada1, Y. Kitou1, Y. Iwadate2, A. Nozaki2, G.S. Slavin3, Y. Fujinaga1, M. Kadoya1; 1Matsumoto/JP, 2Hino/JP, 3Milwaukee, WI/US Purpose: SMART1Map is a novel method for true T1 relaxometry using saturation recovery sequence. The purpose of this study was to clarify the usefulness of native T1 (nT1) of the liver obtained by SMART1Map comparing to other MR imaging biomarkers in the evaluation of the severity of the chronic liver diseases according to the liver stiffness (LS) measured by MR elastography (MRE). Material and methods: We evaluated consecutive 41 patients who underwent magnetic MR imaging including MRE, SMART1Map, IDEAL-IQ, diffusion weighted imaging (DWI) using 1.5-T MR scanner for the evaluation of chronic liver diseases from January to December 2016 in our hospital. The several MR imaging biomarkers of the liver, such as LS, nT1, fat fraction (FF), R2*, and apparent diffusion coef cient (ADC) were obtained. The correlation between LS and the other imaging biomarkers were statistically analyzed including stepwise linear regression analysis on LS using the other imaging biomarkers as explanatory factors. Results: Correlation coef cient and its P value between LS and the other imaging biomarkers were as follows: nT1, r=0.7156 (P<0.01); FF, r=0.1996 (P=0.2363); R2*, r=-0.2955 (P=0.0717); ADC, r=0.2995 (P=0.0605). Stepwise linear regression analysis revealed that nT1 was statistically signi cant explanatory factor for LS, and that the other factors were not signi cant. Conclusion: nT1 of the liver obtained by SMART1Map is signi cant predictor of the LS independent from fat deposition and iron overload of the liver. SS 4.9 The negative hepatic arterial buffer response: pre and post-prandial changes in total liver and hepatic arterial blood flow measured using caval subtraction phase contrast MRI in normal volunteers M. Chouhan, A. Bainbridge, M. Lythgoe, R. Mookerjee, S. Halligan, S.A. Taylor; London/GB Purpose: Non-invasive measurements of total liver blood ®ow (TLBF) and hepatic arterial ®ow (HAF) would be valuable in the assessment of portal hypertension. The purpose of this study was to study changes in TLBF and HAF following prandial stress, known to increase portal venous ®ow (PVF). Material and methods: Fasted healthy volunteers (n=13), underwent PV, proximal and distal IVC breath-hold,cardiac-gated 2D cine-phase-contrast MRI(PCMRI, 5 mm slice thickness, =10˚, 256x256(FExPE)) at 3T, with velocity encoding settings of 40,60 and 80cm/s. TLBF was estimated by subtracting proximal IVC ®ow (above renal but below hepatic venous inlets) from distal IVC ®ow (above hepatic venous inlets,but below the IVC-right atrial junction). HAF was estimated by subtracting PV ®ow from estimated TLBF. Subjects then ingested a 700 calorie nutrient milkshake with a second scan 45-60 minutes later. Data was analysed using paired Student t-tests. Results: As expected, a signi cant rise in post-prandial PVF was observed (56.9±3.6 vs 109.1±4.6 ml/min/100g; p<0.0001). A signi cant rise in postprandial estimated TLBF was also observed (72.0±4.8 vs 117.4±5.0 ml/ min/100g; p<0.0001). Reductions in post-prandial estimated HAF (12.0±4.8 vs 3.8±3.4 ml/min/100g; p=0.0592) were non-signi cant, but reductions in estimated HA fraction (20.2±2.5 vs 8.2±1.3%; p=0.0003) were signi cant. Conclusion: Caval subtraction PCMRI can be used to measure changes in TLBF and HAF after haemodynamic stress. A negative relative hepatic arterial buffer response (reduction in estimated HA fraction in response to the rise in PVF) was observed following prandial stress. SS 4.10 Non-invasive evaluation of clinically significant portal hypertension: validation of two novel algorithms combining liver and spleen stiffness using shear-wave elastography in a large independent cohort of patients with cirrhosis M. Ronot, L. Elkrief, M. Dioguardi Burgio, M. Zappa, L. Castera, V. Vilgrain, P.-E. Rautou; Clichy/FR Purpose: To externaly validate the accuracy of two recent algorithms using sequential measurements of liver (L-SWE) and spleen stiffness (S-SWE) for ruling-out or ruling-in clinically signi cant portal hypertension (CSPH) in a large independent cohort of patients with cirrhosis. Material and methods: 163 consecutive patients with stable cirrhosis (median 55 years; 76% male; Child-Pugh A 38%, B 26% and C 34%) who underwent L-SWE and S-SWE at the time of HVPG measurement were studied. The diagnostic performances of the 2 algorithms were assessed using sensitivity (Se), speci city (Sp), positive predictive value (PPV) and negative predictive value (NPV), as well as the proportion of correctly classi ed patients. Results: The median HVPG was 16 mmHg, and 80% of the patients had CSPH. The  rst published algorithm, using L-SWE<16.0kPa and then SSWE<26.6kPa could ruled-out CSPH with a NPV of 96.3%. Diagnostic performance was lower in our population with a NPV of 60%. The second published algorithm, using L-SWE>38.0kPa, or L-SWE≤38.0kPa but S-SWE>27.9kPa, could ruled-in CSPH with a PPV of 95.7%. Again diagnostic performance in our population was lower with a PPV of 87%. The diagnostic performances of these algorithms did not improve when restricting the analyses to the subset of 68 patients without previous decompensation of cirrhosis. Conclusion: Diagnostic accuracies of algorithms based on sequential measurements of liver and spleen stiffness using SWE are acceptable, but not good enough to replace HVPG measurement or to base clinical decisions. Alexandra Trianti Hall Scienti c Session SS 5 Best rated papers on focal liver lesions SS 5.1 Additional value of contrast-enhanced ultrasonography on fusion-guided percutaneous biopsies of focal liver lesions: prospective feasibility study H.-J. Kang, J.H. Kim, S.M. Lee, H.K. Yang, I. Joo, S.J. Ahn, J.K. Han; Seoul/KR Purpose: To determine the value of contrast-enhanced ultrasonography (CEUS) on real-time fusion-guided percutaneous biopsies of focal liver lesions. Material and methods: Thirty-six patients with focal liver lesions were prospectively enrolled. For biopsy planning, real-time imaging fusion of CT/MRI with USG (hereafter USG-Fusion) was performed and subsequently real-time SonoVue-enhanced USG was fused with CT/MRI (hereafter CEUS-Fusion) in all patients. Biopsy operator was evaluating lesion visibility, necrotic degree, con dence level of technical success before procedure (4-point scale), and safety root accessibility on conventional USG (step 1), USG-Fusion (step 2), and CEUS-Fusion (step 3). Occurrence of change in biopsy target also assessed. Results: Among 36 target lesions, 8 (22.2%) lesions were invisible on Step 1 and 2. After applying the CEUS fusion, 7 of 8 (87.5%) focal hepatic lesions were visualized. Con dence level of technical success before procedure is signi cantly increased on CEUS-Fusion compared Step 1 (p=0.029) or 2 (p=0.002). Presumed target lesion were changed in 16 of 36 (44.4%) patients after CEUS-Fusion, and as the lesion is more necrotic, the presumed target lesions were more frequently changed (61.2%, 13/21 necrotic mass; 20%, 3/15 non-necrotic mass). Con rmative diagnostic results were reported in 35 patients (97.2%, 33 malignant and 2 benign). Accessibility of safety root to target lesion did not reach statistical differences. Conclusion: Applying real-time CEUS fusion with CT/MRI improved tumor visibility and viable portion assessment, and leading to higher operator con dence and diagnostic yield, comparing conventional USG and real-time CT/ MRI fusion with USG. SS 5.2 The impact of a liver specific multidisciplinary assessment in patients with colorectal cancer liver metastases: a population-based study J. Engstrand1, N. Kartalis1, C. Strömberg1, M. Broberg1, A. Stillström1, T. Lekberg1, E. Jonas2, H. Nilsson1, J. Freedman1; 1Stockholm/SE, 2Cape Town/ZA Purpose: To evaluate the potentially improved resection rate in a de ned cohort if all patients with colorectal cancer (CRC) liver metastases (LM) were evaluated at a dedicated liver multidisciplinary tumour-board (MDT). Material and methods: A retrospective analysis of 272 patients diagnosed with LM within a 5-year follow-up period after CRC-diagnosis in the greater Stockholm region was conducted. All patients with LM were re-evaluated at a  ctive liver-MDT where previous imaging studies, tumour characteristics, medical history and patients’ treatment preferences were presented. Treatment decisions for each patient were compared to the decisions at the original MDT. Odds ratios (ORs) and 95% con dence intervals were estimated (logistic regression) for factors associated with referral to the liver-MDT. Results: Out of 272, 102 patients were discussed at an original MDT and 69 patients were eventually resected. At the  ctive liver-MDT, a further 22 patients were considered as resectable/potentially resectable, none previously assessed at liver-MDT. At the original MDT, 47 (18%) patients had inadequate imaging; in additional 27 (10%) patients the available imaging was inadequate but other patient-related factors permitted decision-making on treatment strategy. Factors in®uencing referral to liver-MDT were age (OR 3.12, 1.72 to 5.65), American Society of Anesthesiologists (ASA) score (OR 0.12, 0.01 to 1.17, ASA 2 versus ASA 4) and number of LM (OR 0.10, 0.04 to 0.22, 1-5 LM versus >10 LM), while gender (p=0.194) and treatment at a teaching hospital (p=0.838) were not. Conclusion: A substantial number of patients with CRC liver metastases are not managed according to best available evidence and the potential for higher resection rates is high. SS 5.3 Can CT texture features predict imminent development of hepatic colorectal metastatic disease? S.J. Lee, M. Lubner, D. Kim, P. Pickhardt; Madison, WI/US Purpose: Preclinical studies have demonstrated CT textural changes in liver enhancement related to micrometastases, and early human clinical studies have suggested that these changes may be associated with the eventual development of hepatic metastases. The purpose of this study was to determine if hepatic textural changes are present at CT in patients immediately prior to the development of grossly detectable colorectal liver metastases, compared to those without liver metastatic spread. Material and methods: This case-control study was comprised of 89 colorectal cancer patients (29 cases who developed liver metastases and 60 controls who did not). Liver texture features were assessed on portal-venous phase CT using a software tool (TexRAD) at both pre-treatment staging and interval surveillance scans immediately prior to metastatic detection. Matched interval scans were also assessed in controls. Multivariate Cox proportional hazards models were  tted with time to occurrence of liver metastases as the primary outcome. Results: After adjusting for multiple hypothesis testing, none of the features were different between cases and controls. Both models of staging and interval CT texture features failed to reach statistical signi cance (p = 0.06, p = 0.13 by likelihood ratio testing). Staging and interval entropy values were also not associated with hepatic metastatic disease (p = 0.61, p = 0.62). Conclusion: We found no evidence that liver parenchymal texture features from contrast-enhanced staging or interval pre-detection CT scans could predict the subsequent development of hepatic metastasis in colorectal cancer patients. SS 5.4 Intravoxel incoherent motion (IVIM) of colon cancer liver metastases for the response assessment of antiangiogenic treatment: preliminary results A. Oz, E. Namal, S. Server, B. Koyuncu Sokmen, S.B. Barlas, N. Inan, C. Balci; Istanbul/TR Purpose: To evaluate the time related intra-voxel incoherent motion (IVIM) parameter changes of colon cancer liver metastases during anti-angiogenic therapy. Material and methods: Eight-patients with 16 liver metastases were included in this prospective study. All patients were treated with anti-angiogenic agent Bevacizumab in combination with FOLFOX-FOLFIRI. All patients were examined pretreatment (PT) as well as at the 3rd, 6th, and 9th months of therapy. MRI was performed with a 1.5T scanner. In addition to routine abdominal MRI, an IVIM-DWI sequence was obtained using a free breath single-shot echo planar spin-echo (EPI) sequence with 17 different b factors (0-1400s/mm2). The mean D (true diffusion coef cent), D* (pseudo-diffusion coef cient associated with blood ®ow), and f (perfusion fraction) values of each metastasis were calculated for each time point and time related changes were recorded. Results: Compared to the value of PT; both f and D* values of the metastases were signi cantly decreased at the time point 6 months after the initiation of anti-angiogenic therapy (p<0.001). The time-related changes of the mean f value were as follows: 0.2035, 0.2552, 0.3024, and 0.2492 at PT, 3rd, 6th, and 9thmonths; of the mean D* values were: 84.486x10-3, 197.911x10-3, 188.241x103, 121.853x10-3 at PT, 3rd, 6th, and 9th months, respectively. Conclusion: The f value of IVIM may quantitatively re®ect the response of antiangiogenic therapy. The effect of anti-angiogenic response becomes evident after 9 months of therapy. SS 5.5 Benign hepatocellular tumors : correlation between quantitative uptake of Gd-BOPTA on hepatobiliary phase and molecular background E. Reizine, G. Amaddeo, F. Pigneur, L. Baranes, F. Legou, B. Zegai, V. Roche, A. Rahmouni, J. Calderaro, A. Luciani; Creteil/FR Purpose: The purpose of our study was to correlate in benign hepatocellular tumors the quantitative analysis of HBP contrast agent uptake to the quantitative level of OATP expression. Material and methods: This single-center retrospective study included between September 2009 to March 2015, 20 consecutive patients with a proven pathological and immunohistochemical (IHC) diagnosis of FNH or liver adenoma and underwent Gd-BOPTA-enhancement MRI, including the realisation of HBP. The analysis of HBP utpake was performed using the Liver to Lesion Contrast Enhancement Ratio (LLCER). The mean LLCER and OATP expression were calculated and compared between FNH and HCA (Mann-Whitney) and expression of OATP were correlate with LLCER value (Spearman). Results: Of the 23 hepatocellular benign tumors 9 (39%) were FNH and 14 (61%) were HCA. On HBP 100% of the FNH appeared either hyperintense or isointense and 79% of the adenomas appeared hypointense. The mean OATP expression of FNH (46,67+/-26,58%) was signi cantly higher than that of HCA (22,14+/-30,74%) (p=0,0273) and the mean LLCER of FNH (10,66 +/- 7,403%) was signi cantly higher than that of HCA (-13,5 +/- 12,25%) ( p<0,0001). A signi cant correlation was found between OATP expression and LLCER values in all patients (r=0,661; p =0,0006). Conclusion: The quantitative analysis of HBP lesion uptake is correlated to quantitative OATP expression in benign hepatocellular tumors, and can help for the differential diagnosis of FNH, -catenin-activated HCA and other HCA. Scienti c Session SS 6 Small and large bowel luminal imaging SS 6.1 MR enterography in Crohn’s disease: comparison between diffusion-weighted imaging and intravenous contrast material in detection of active disease E. Demozzi, M.L. Monti, L. Romano, G. Foti, A. Geccherle, G. Carbognin; Verona/IT Purpose: To determine the performance of diffusion-weighted imaging magnetic resonance enterography (DWI-MRE) compared to contrast material-enhanced MR enterography (CE-MRE) for evaluating bowel in®ammation activity in Crohn’s disease (CD). Material and methods: We retrospectively review 55 consecutive adults patients with CD that underwent clinical assessment, MR enterography, and ileocolonoscopy within 4 weeks. Inclusion criteria were: a) DWI-MRE with the following b values (50, 400 and 800 s/mm2) and CE-MRE and b) histologically examination after colonoscopy. The  nal study population included 39 patients (19 M, 20 F, mean age 42 years). The results were compared with the histopathological examination after colonoscopy as the reference standard. The sensitivity (se), speci city (sp), positive predicting value (PPV), negative predicting value (NPV) and accuracy (acc) of DWI and CE-MR enterography in distinguishing active in®ammatory lesions from inactive lesions were determined. Results: DWI yielded se, sp, PPV, NPV and acc of 88%, 82%, 91%, 75% and 86%, respectively, in distinguishing active in®ammatory lesions from inactive lesions. Conversely, se, sp, PPV, NPV and acc obtained using CE-MR were 88%, 64%, 84%, 70% and 80%, respectively. Conclusion: DWI-MR enterography was superior to CE-MR enterography for the evaluation of in®ammation in Crohn disease, and could be considered as a potential biomarker of active in®ammation in CD. SS 6.2 Comparison of contrast-enhanced and diffusionweighted MRI in assessment of the terminal ileum in Crohn’s disease patients C.A.J. Puylaert1, J.A.W. Tielbeek1, P.J. Schüf®er2, C.Y. Nio1, K. Horsthuis1, B. Mearadji1, C.Y. Ponsioen1, F. Vos3, J. Stoker1; 1Amsterdam/NL, 2New York, NY/US, 3Delft/NL Purpose: To compare the performance of contrast-enhanced (CE)-MRI and diffusion-weighted imaging (DW)-MRI in grading Crohn’s disease activity at the terminal ileum. Material and methods: Three readers evaluated CE-MRI, DW-MRI and their combinations (CE/DW-MRI and DW/CE-MRI, depending on which protocol was used at the start of evaluation). Disease severity grading scores were correlated to the Crohn’s Disease Endoscopic Index of Severity (CDEIS). Diagnostic accuracy, severity grading and levels of con dence were compared between imaging protocols and interobserver agreement was calculated. Results: Sixty-one patients were included (30 female, median age 36). Diagnostic accuracy for CE-MRI, DW-MRI, CE/DW-MRI and DW/CE-MRI ranged between 0.82–0.85, 0.75–0.83, 0.79–0.84 and 0.74–0.82, respectively. Severity grading correlation to CDEIS ranged between 0.70–0.74, 0.66–0.70, 0.69–0.75 and 0.67–0.74, respectively. For each reader, CE-MRI values were consistently higher than DW-MRI, albeit not signi cantly. Con dence levels for all readers were signi cantly higher for CE-MRI compared to DW-MRI (P<0.001). Further increased con dence was seen when using combined imaging protocols. Conclusion: There was no signi cant difference of CE-MRI and DW-MRI in determining disease activity, but the higher con dence levels may favor CEMRI. DW-MRI is a good alternative in cases with relative contraindications for the use of intravenous contrast medium. SS 6.3 Comparison of diagnostic performance between 1 mSv CT enterography and half regular dose CT enterography for evaluating active inflammation in patients with Crohn’s disease S.H. Kim, J.H. Son, J.-H. Yoon, Y. Lee; Busan/KR Purpose: To compare the diagnostic performance between ultralow-dose CT enterography (CTE) images obtained at 1 mSv and half regular dose CTE images for evaluating active in®ammation in patients with Crohn’s disease. Material and methods: 46 consecutive patients (39 men and 7 women; mean age 29 years; range 15-59 years) with Crohn’s disease underwent CTE. CT protocol consisted of enteric phase regular-dose, portal venous phase halfdose with adaptive statistical iterative reconstruction (ASIR) and 90-s delayed ultralow-dose scans with FBP and ASIR under a  xed 120 kVp and a variable mAs. Two blinded readers independently recorded their con dence score for active in®ammation in jejunum, ileum and terminal ileum on each image data set. The diagnostic performance of each image set was compared by pairwise comparison of ROC curves. The  ndings on regular dose scan and ileocolonoscopy served as the reference standard. Results: A total of 138 bowel segments were analyzed. The mean effective doses of regular, half-dose and ultralow-dose scans were 6.7, 3.7 and 1.2 mSv, respectively. For one reader, the diagnostic performance was increased in the order of ultralow-dose with FBP, ultralow-dose with ASIR, and half-dose with ASIR (AUC, 0.757, 0.804, 0.837; P=0.0292, P=0.0430, respectively). For another reader, it showed no signi cant difference among the three image sets (AUC, 0.865, 0.881, 0.884; P=0.1683, P=0.8438, respectively). Conclusion: The diagnostic performance of 1 mSv CTE may be comparable to that of half-dose CTE. SS 6.4 Diagnostic value of quantitative dynamic contrastenhanced MR imaging with perfusion analysis in vascular assessment between inflammatory and fibrotic lesions in patients with Crohn’s disease D. Ippolito, S. Lombardi, C. Talei Franzesi, A. Casiraghi, S. Sironi; Monza/IT Purpose: To determine the diagnostic value of dynamic contrast-enhanced perfusion-MRI in detection and characterization between active small bowel in®ammation and mural  brosis in patients with Crohn’s disease (CD). Material and methods: We analyzed a total of 37 patients (11 women; 23-69 years) with known biopsy proven CD, who underwent MR-enterography study, performed on a 1.5T MRI system (Achieva, Philips), using a phased array sense body multi-coil, after oral administration of 1,5-2 of PEG solution. MRE protocol included T1 weighted, sSShT2, sBTFE and gadolinium-enhanced THRIVE sequences acquired on coronal and axial planes. A dedicated workstation was used to generate colour permeability maps, and after placing the Region of interest (ROI) on the bowel site involved by CD localization, the following parameters were calculated and statistically analyzed: relative arterial, venous and late enhancement (RAE, RVE, RLE), maximum enhancement (ME) and time to peak (TTP). Results: Perfusion images have demonstrated a good correlation with MRE  ndings, and 26 out of 37 patients showed an active in®ammatory disease with following perfusion parameters: RAE (%) median=116.1; RVE (%) 125.3; RLE (%) 127.1; ME (%) 1054.7; TTP (s) 157. The same parameters calculated in patients with mural  brosis were: REA= 56.4; RVE = 81.2, RLE= 85.4; M =809.6; TTP=203.4. Signi cant differences (p< 0.001) regarding all perfusion parameters evaluated between active in®amed and  brotic bowel wall vascularity characteristics was found, obtaining higher values in active Crohn’s disease bowel site. Conclusion: CD vascular assessment by dynamic contrast perfusion-MR analysis represents a complementary diagnostic tool for identifying the activity of bowel in®ammation, thus allowing assessment of treatment response. SS 6.5 Magnetic resonance enterography in the assessment of terminal ileitis in patients suspected to have Crohn’s disease in the Chinese population. K.W.H. Chiu1, W.-K. Seto1, Y.-S. Lin2, T.-H. Ren2, J.-Q. Guo2, X.-F. Li2, X.P. Shen2; 1Hong Kong/HK, 2Shenzhen/CN Purpose: To investigate the ef cacy of magnetic resonance enterography (MRE) in patients with endoscopically diagnosed terminal ileitis (TI) and suspected to be Crohn’s disease (CD). Material and methods: Retrospective review of a prospective database of patients referred to our institute with suspected Crohn’s disease. Patients were included if they underwent MRE and colonoscopy for suspected CD. All MRE were performed on a 1.5T scanner (Magnetom Avanto, Siemens Healthcare, Erlangen, Germany) with the same protocol. Images were independently reviewed by two board-certi ed radiologists blinded of clinical information and the results were compared to endoscopic and pathology  ndings. Results: Seventy-two patients (median age 37, 53M:19F) were included with all but one one scan deemed adequate for analysis. Inter-observer agreement for abnormality on MRE was high (keppa=0.91) and pathology was identi ed on 43 scans of which 39 (90.7%) involved the terminal ileum and 26 (60.4%) had multi-segment disease. Twenty-eight patients had histologically con rmed Crohn’s disease, 6 TB enteritis, 2 intestinal Behcet’s disease and 1 oesinophilic gastroenteritis. MRE has sensitivity of 85.7% and the presence of skip lesions has 100% speci city for CD. However, isolated MRE TI was also in seen all TB enteritis and 1 intestinal Bechet’s. Conclusion: Our results show MRE compares favorably to colonoscopy in the detection of CD in the Chinese population where the incidence is much lower than the West. However, for isolated TI, other differential diagnoses should be considered. SS 6.6 MR-Enterography: small-bowel wall-thickening diseases not associated with Crohn’s disease G. Skouroumouni, D. Panagiotidou, G. Papaderakis, I. Petmezaris, M. Lelegianni, A. Morichovitou, I. Tsitouridis; Thessaloniki/GR Purpose: In this study, we describe our experience with MR-Enterography (MRE) in accessing small-bowel wall-thickening diseases, other than its main use, that of Crohn’s disease. Material and methods: We have retrospectively reviewed 227 consecutive patients who underwent MRE in our institution during a two-year period (January 2015-December 2016). We document and evaluate all other small-bowel wall-thickening diseases, including benign and malignant neoplasms, other in®ammatory bowel diseases, infectious processes and celiac disease. All of the patients had a  nal diagnosis on the basis of the clinical presentation, follow-up, and in some cases histological proof. Results: 25 patients (11.01%) with small-bowel wall-thickening diseases other than Crohn’s disease were found. 11 out of 227 (4.85%) patients had benign and malignant neoplasms arising in isolation or in polyposis syndromes, 9 patients (3.08%) had non-speci c terminal ileitis and were  nally diagnosed with intestinal infections, such as Yersinia enterocolitica, 1 patient (0.44%) had ulcerative colitis with backwash ileitis, 2 patients (0.88%) were diagnosed with eosinophilic gastroenteritis and 6 patients (2,64%) had celiac disease. Conclusion: MRE can be a useful diagnostic modality in small bowel diseases, which are not associated with Crohn’s disease, and are dif cult to access with other diagnostic modalities. Therefore, radiologists should be familiar with the imaging appearances of these conditions. SS 6.7 Semi-automatic assessment of the small bowel and colon in Crohn’s disease patients using MRI (the VIGOR++ project) C.A.J. Puylaert1, P.J. Schüf®er2, R.E. Naziroglu3, J.A.W. Tielbeek1, Z. Li3, J. Makanyanga4, C. Tutein Nolthenius1, C.Y. Nio1, D. Pendse4, A. Menys4, C.Y. Ponsioen1, D. Atkinson4, A. Forbes4, J.M. Buhmann5, T. Fuchs2, H. Hatzakis4, L.J. Van Vliet3, J. Stoker1, S.A. Taylor4, F. Vos3; 1Amsterdam/NL, 2New York, NY/US, 3Delft/NL, 4London/GB, 5Zurich/CH Purpose: MRI scores show promise for evaluation of Crohn’s disease (CD) activity, although reported reproducibility is variable. Potentially, reproducibility could be improved by use of computer-assisted semi-automated measurements to reduce interobserver variation. The aim of this study was to develop and validate a predictive MRI activity score for ileocolonic CD activity based on computer-assisted semi-automatic measurements of MRI features. Material and methods: The “VIGOR” MRI activity score was developed using subjective radiologist observations and semi-automatic measurements of mural thickness, excess bowel wall volume and DCE (initial slope of increase; ISI) using a retrospective cohort of 27 CD patients against the CDEIS. A subjective score was developed using only radiologist observations. For validation, scores were applied by two observer groups to a prospective dataset of 106 CD patients (59 female, median age 33), along with three existing MRI activity scores (MaRIA, London score and CDMI). Results: The VIGOR score (17.1*ISI+0.2*excess volume+2.3*mural T2) showed moderate correlation to CDEIS (r=0.58–0.59), which was comparable to other activity scores (r=0.34–0.51,p>0.05). The VIGOR score had a signi cantly higher interobserver agreement than other activity scores (ICC=0.81 vs. 0.44–0.59, p<0.001). Comparable diagnostic accuracy was seen for the VIGOR score (80%–81%) to other activity scores (70%–86%). Conclusion: The new VIGOR score achieves comparable accuracy to conventional MRI activity scores, but with signi cantly improved reproducibility, favouring its use for therapy evaluation and monitoring of disease activity. SS 6.8 CT colonography: positive predictive value of C-RADS C3c classification for diagnosis of colorectal cancer D. Valencia, M. Farthing, H. Stunell, D. Boone; Colchester/ GB Purpose: To establish the positive predictive value of C-RADS C3c classi cation for diagnosis of colorectal cancer. To identify morphological factors associated with malignancy. Material and methods: Two experienced GI radiologists reviewed all CT colonography (CTC) studies carried out between 20/10/2011-1/4/2016. Both observers categorised extracolonic  ndings according to C-RADS criteria and discrepancies were resolved by consensus. A resident, blinded to study purpose, performed a retrospective review of relevant databases and case-notes for all patients classi ed with an indeterminate stricture (C-RADS C3c) to establish histopathological and clinicoradiological outcomes. Strictures were assessed for shouldering, mural thickness, ulceration, perienteric stranding and lymphadenopathy. Descriptive statistics were produced. Results: In total 1646 studies were performed (94% symptomatic; 6% screening) with a median follow-up 20months (range 1-55). Of a total 73 patients classi ed C-RADS C3c, 14 were deemed too frail or refused further investigation, 4 died of unrelated conditions, 45 underwent endoscopy and 7, interval CTC. Diverticular strictures were con rmed in all cases. The positive predictive value was 0 for cancer and 100% for diverticular stricture. Consequently, no meaningful analysis of morphological features suggestive of underlying malignancy could be performed. Conclusion: In our series, all patients classi ed as CRADS C3c were con rmed as having benign disease by either endoscopy or clinicoradiologic follow-up. Further research to compare morphological characteristics of benign and malignant strictures is required to avoid unnecessary endoscopy. SS 6.9 Imaging features of missed colon cancers on non targeted abdominal CT: assessment of the missed diagnosis rate M.M. Amitai, M. Eifer, U. Kopilov, V. Belsky, E. Klang; Ramat Gan/IL Purpose: To assess the missed diagnosis rate of colon cancer on non-targeted abdominal CT and to evaluate the imaging features characteristic of missed cancers. Material and methods: Consecutive patients diagnosed with colorectal cancer by colonoscopy that underwent an abdominal CT scan for reasons other than tumor evaluation within a year before the colonoscopy were included. Missed diagnosis rate by the original radiologists that interpreted the CTs was evaluated. A repeat interpretation oriented for colon cancer detection was separately obtained by two radiologists (study readers) who were blinded to tumors’ location. The study readers analyzed the imaging features of detected tumors (shape, length, l wall thickness, free ®uid, fat stranding, vessel engorgement, stenosis and lymphadenopathy). Associations of imaging features and cancer misses were evaluated. Results: 127 patients were included. Missed diagnosis rate by the original readers was 25/127 (19.7%). Each study reader could not identify the cancer in 8/127 (6.3%) patients. Imaging features associated with misses were absence of fat stranding (p=0.007, p=0.003), absence of vessel engorgement (p<0.0001, p<0.0001) and absence of lymphadenopathy (p=0.005, p=0.004). Missed tumors were shorter than non-missed (1st  reader: 33.2±11.9mm vs. 51.4±18.2mm; 2nd reader: 32.5±9.6mm vs. 61.3±23.4mm; p<0.001). Conclusion: Physicians should be aware that if no tumor was reported on an abdominal CT report: it does not rule out cancer. The tumor length, absence of fat stranding, vessel engorgement and lymphadenopathy are contributing factors for missed cancers. SS 6.10 Ileal neuroendocrine tumours with mesenteric involvement: suggestions for an improved pre-surgical risk stratification with multi-phase CT L. Funicelli, F. Zugni, E. Bertani, F. Ferrari, N. Fazio, M. Bellomi; Milan/IT Purpose: To suggest additional CT features for the pre-surgical risk strati cation of patients with small intestinal neuroendocrine tumours (siNETs), and to provide preliminary analysis of the performance of such criteria on our patient database. Material and methods: We employed the recently proposed classi cation of mesenteric nodules associated with siNETs, based on superior mesenteric artery (SMA) in ltration [Lardière-Deguelte et al], including as additional criteria the degree of superior mesenteric vein (SMV) in ltration and the presence of extensive mesenteric retraction. A radiologist with 5 years of experience in the staging of siNETs retrospectively and blindly reviewed the images of patients scheduled for surgery in our institution (2006-2016) providing a strati cation into either high-risk or low-risk for unresectability. Results were matched to the surgical reports. Results: 20 multi-phase CT scans of patients with siNETs were selected for evaluation. All 5 patients in the high-risk group had received non-curative surgery (impossible or incomplete resection). Of these, 1/5 was classi ed into the high-risk group for the presence of severe SMV in ltration alone, and 1/5 only for the presence of extensive mesenteric retraction. Fourteen patients in the low-risk group had received curative surgery (14/15), while one (1/15) was unresectable due to the primary tumour extension. Conclusion: The CT evaluation of SMV in ltration and mesenteric retraction, in addition to the standard evaluation of SMA in ltration allowed a correct presurgical risk strati cation in the majority of patients. SS 8.3 Transarterial chemoembolization of liver metastasis from uveal melanoma using melphalan and calibrated microspheres: treatment response and complications X. Carle, A. Rudel, J.P. Caujolle, J. Thariat, L. Gastaud, P. Chevallier; Nice/FR Purpose: To investigate the ef cacy and safety of hepatic transarterial chemoembolization (TACE) using melphalan and microspheres in patients with liver metastasis from uveal melanoma (UM). Material and methods: Monocentric retrospective study from 2006 to 2016 including 35 consecutive patients with liver metastasis from ocular melanoma treated by TACE using melphalan and calibrated microspheres (250μm). Radiological response was assessed according to RECIST 1.1, m RECIST and EASL on contrast-enhanced CT or MRI. The primary endpoint was the overall survival (OS). Liver metastasis response (LMR) and complications evaluated with the common terminology criteria for adverse events (CTCAE) were secondary endpoints. Results: The 35 patients underwent 139 TACE (mean, 4.0 sessions; range 1–9) with an OS of 22.5 months (range 2–63). LMR combining partial and complete response was 46%, 90%, 90% with RECIST 1.1, mRECIST and EASL, respectively. There were 24 major complications (CTCAE > 3) in 14 patients including 2 deaths due to septic shock. Conclusion: For patients with liver metastases from UM, the TACE using melphalan showed good results on OS comparatively to previous reports and also on LMR with an acceptable rate of complications. This treatment seems to shift the prognosis for most of the patients on other secondary locations. SS 8.4 Switching bipolar radiofrequency ablation using cooledwet electrodes for treatment of HCC: a preliminary study W. Chang, J.M. Lee, J.H. Yoon, D.H. Lee, J.K. Han, S.M. Lee, T.-H. Kim, B.R. Kim, S. Lee1; Seoul/KR Purpose: To prospectively evaluate the therapeutic effectiveness of switching bipolar (SB) radiofrequency ablation (RFA) using cooled-wet electrodes in HCCs, and to compare it with switching monopolar (SM) RFA using separable clustered electrodes. Material and methods: This prospective study was approved by the Institutional Review Boards. Between November 2013 and January 2015, sixty-nine HCC patients were prospectively enrolled and randomized into two groups. Seventy- ve lesions of those patients were treated by RFA using cooled-wet electrodes with switching bipolar mode (SB-RFA group, n=36) or separable clustered electrode with switching monopolar mode (SM-RFA group, n=39). Technical parameters including number of ablation, ablation time, volume, energy delivery, and complications were evaluated. Thereafter, 1-year and 2-year local tumor progression (LTP)-free survival rates were compared between two groups. Results: In SB-RFA group, number of ablations was smaller (1.72±0.91 vs. 2.36±1.57, P=0.038), ablation time was shorter (11.1±4.5 vs.15.4±6.1 min, P=0.001), and energy delivery was smaller (13.6±6.7 vs.23.5±12.9 kcal, P<0.001). Ablation volume was not signi cantly different between SB-RFA and SM-RFA groups (61.8±24.3 vs.54.9±23.7cm3, P=0.229). Major complications occurred in one patient in the SM-RFA group. Technical failure occurred in one patient of each groups. The 1-year and 2-year LTP-free survival rates were 93.9%, 84.3% in the SB-RFA group and 92.1%, 86.4% in the SM-RFA group (P=0.905). Conclusion: SB-RFA using cooled-wet electrodes provides smaller number of ablations, shorter ablation time and comparable LTP-free survival rates compared to those of SM-RFA. SS 8.6 Evaluation of HCC response to loco-regional therapy: validation of response criteria with MRI using explant as a reference S. Gordic, I. Corcuera-Solano, A. Stueck, P. Guniganti, P. Argiriadi, M. King, S. Thung, B. Taouli; New York, NY/US Purpose: To assess the performance of various imaging response criteria for the prediction of histopathologic tumor necrosis of HCC post-locoregional therapy on liver explant. Material and methods: 61 patients (M/F 46/15, mean age 60y) who underwent liver transplantation after loco-regional therapy with transarterial chemoembolization plus radiofrequency ablation (n=56) or 90Yttrium radioembolization (n=5) were included in this retrospective study. All patients underwent MRI using routine liver protocol using gadolinium-based contrast agents with image subtraction within 90 days of transplant. The following criteria were assessed by 3 independent readers: RECIST, mRECIST, EASL, percentage of necrosis on subtraction images (on arterial and portal venous phases), and qualitative/quantitative diffusion-weighted imaging (signal intensity and ADC). Degree of tumor necrosis/viability was retrospectively assessed in all index tumors at histopathology. Logistic regression and ROC analyses were used to determine predictors of complete pathologic necrosis (CPN=100%). Results: 97 HCCs (mean size 2.3±1.3 cm) including 28 that were 100% necrotic were evaluated. mRECIST, EASL and % necrosis (arterial and portal venous phases) were all signi cant predictors of CPN (AUC 0.840–0.864, p <0.05) while RECIST and DWI criteria were not. Conclusion: mRECIST, EASL criteria and percentage of necrosis on subtraction images are all signi cant predictors of CPN in HCC post loco-regional therapy. SS 8.7 HCC treated with 90Yttrium radioembolization: can pre-treatment and 6-week post-treatment volumetric apparent diffusion coefficient (ADC) histogram measurements predict subsequent tumor response? S. Gordic1, M. Wagner2, R. Zanato3, S. Hectors1, C. Besa1, E. Kim1, B. Taouli1; 1New York, NY/US, 2Paris/FR, 3Padova/IT Purpose: To assess the potential of volumetric ADC (vADC) histogram measurements obtained before and 6 weeks (6w) post-treatment for prediction of HCC response to 90Yttrium radioembolization (RE). Material and methods: 22 patients (M/F 15/7, mean age 65y) who underwent RE were included. MRI using routine liver protocol including DWI (b= 50, 400, and 800 s/mm2) was performed pre-treatment and 6w and 6 months (6m) after RE. Two readers in consensus assessed tumor response 6m after RE. De nition of complete (CR) or partial response (PR), stable disease (SD), and progression (PD) for each index tumor was based on mRECIST. vADC parameters (mean, median, mode, min, max, kurtosis and skewness) at baseline and 6w were obtained by placing ROIs on the ADC map covering the tumors. Results: 26 HCC lesions (mean size 3.4±2.4 cm) were assessed. vADC mean, median and mode at 6 w were signi cantly higher in patients with CR/PR compared to patients with SD/PD (1.76–1.81 vs. 1.23–1.34 x10-3 mm2/s, p=0.013– 0.024), while there was no signi cant difference between the two groups at baseline. vADC mean, median and mode at 6w were signi cant predictors of CR/PR (AUC 0.776, 0.788, 0.764; p=0.002–0.004) and of CR (AUC 0.750, 0.757, 0.694; p=0.014–0.044) after RE. Conclusion: vADC mean, median and mode at 6w are signi cant predictors of subsequent response in HCCs treated with RE, while pre-treatment vADC does not have any predictive value. SS 8.8 HCC showing complete response according to mRECIST on CT after a first session of conventional chemoembolization: is lipiodol deposition a good predictor of local recurrence? M. Dioguardi Burgio, M. Ronot, M. Lagadec, C. Garcia-Alba, M. Zappa, A. Sibert, V. Vilgrain; Clichy/FR Purpose: To evaluate if the lipiodol deposition pattern can predict local recurrence in HCC nodules with complete response (CR) according to mRECIST on CT after a  rst session of conventional chemoembolization (cTACE). Material and methods: From January 2012 to May 2014 patients undergoing a  rst cTACE session for HCC were identi ed. Inclusion criteria were presence of ≤3 HCCs and available pre- and post-TACE CECT. Response was assessed according to mRECIST. Among HCCs showing CR lipiodol deposition was classi ed as complete (C-Lip, covering the entire tumor volume), or incomplete (I-Lip). Local recurrence was de ned as the reappearance of enhancing areas on arterial phase showing washout on portal/delayed phase within 2 cm from treated tumors on follow-up CT examinations. Results: Final population included 50 patients (mean age 62+/-12 y; 45 male (90%)) with 82 HCCs (mean 26.8+/-14.2 mm). A total of 46 (56%) HCCs were classi ed as CR, including 16 I-Lip (35% - mean 22.9+/-8 mm) and 30 C-Lip (65% - mean 22.8+/-10 mm). After a median follow-up of 14 months (range 3.2–35.9 months), 15/16 (94%) and 10/30 (30%) of I-Lip and C-Lip HCCs showed local recurrence on CT (p<0.001). No difference regarding delay of recurrence was noted between I-Lip and C-Lip HCCs (mean 334 vs. 401 days p=0.519). Conclusion: Despite showing CR according to mRECIST, HCCs with incomplete lipiodol deposition have a high risk of recurrence and should be considered as incompletely treated. SS 8.9 Value of tumor stiffness measured with MR elastography for assessment of response of HCC to locoregional therapy S. Gordic1, J. Bou Ayache1, P. Kennedy1, C. Besa1, M. Wagner2, O. Bane1, R. Ehman3, E. Kim1, B. Taouli1; 1New York, NY/US, 2Paris/FR, 3Rochester, NY/US Purpose: To correlate tumor stiffness (TS) measured with MR elastography (MRE) with degree of tumor enhancement and necrosis on contrast-enhanced T1-weighted imaging (CE-T1WI) in HCC treated with 90Yttrium radioembolization (RE) or transarterial chemoembolization plus radiofrequency ablation (TACE/RFA). Material and methods: In this IRB-approved retrospective study, 52 patients (M/F 38/14, mean age 67y) with HCC who underwent RE (n=22) or TACE/RFA (n=30) and 11 controls (M/F 6/5, mean age 64y) with newly diagnosed untreated HCC were included. The MRI protocol included a 2D MRE sequence. TS was obtained by placing regions of interest (ROIs) over HCCs on stiffness maps. Visual assessment of tumor necrosis on subtraction images and calculation of enhancement ratios by placing ROIs over tumors on CE-T1WI were performed. LS (liver stiffness) was also measured. Results: 63 HCCs (mean size 3.2±1.6 cm) were evaluated. TS was signi cantly lower in treated compared to untreated tumors (3.9±1.8 vs. 6.9±3.4 kPa, P=0.006) and also compared to LS (5.3±2.2 kPa, P=0.002). There were signi cant correlations between TS and each of enhancement ratios (r 0.514, P=0.0001), and percentage of necrosis (r -0.540, P=0.0001). The observed correlations were stronger in patients treated with RE (TS vs. ER, r 0.636, TS vs. necrosis, r -0.711, both P=0.0001). Percentage of necrosis and T1-signal in native T1WI were signi cant independent predictors of TS (P=0.0001, respectively, P=0.001). Conclusion: TS measured with MRE shows a signi cant correlation with tumor enhancement and necrosis, especially in HCCs treated with RE. SS 8.10 Dynamic contrast enhanced perfusion CT imaging as an early predictor for tumour response to sorafenib treatment in patients with advanced HCC lesions D. Ippolito, G. Querques, C. Talei Franzesi, S. Lombardi, S.G. Drago, S. Sironi; Monza/IT Purpose: To determine the prognostic value of CT-perfusion (CT-p) imaging in evaluation of blood ®ow changes related to therapeutic effects of sorafenib by quantitative analysis of tumor vascularization. Material and methods: Eighty-one CT-p studies were performed in 22 patients, with biopsy-proven diagnosis of HCC lesion, who underwent target antiangiogenetic therapy. Perfusion studies were performed at baseline and during treatment follow-up (every 3 months) on 256 multidetector CT (iCT, Philips), with following parameters:100 Kv,100 mAs;16 dynamic slices/scan; 40 dynamic scans; 50 ml of contrast medium. Target lesions and surrounding parenchyma were evaluated using a dedicated perfusion software which generated a quantitative colour map of vascularization. Following perfusion parameters were considered: hepatic perfusion (HP); arterial perfusion (AP); blood volume (BV); hepatic perfusion index (HPI) and time to peak (TTP) and statistically compared between responders (complete response, stable disease or partial response) and non-responders. Results: The group that responded to sorafenib showed a signi cant reduction of values in HCC target lesions after anti-angiogenic therapy (HP 29.4±23.7 vs 51.9±16.8; AP 29.8±25.5 vs 52.2±17.9; p<0.01), in comparison with nonresponder group that demonstrated an increase or no signi cant variation after treatment (HP 42.5±28.3 vs 38.5±11.8; AP 37.5±22.6 vs 35.9±11.2). Moreoever, CT-p values were signi cantly higher (p=0.05) at baseline in the responder group compared to the non-responder, and a higher survival rate was observed in responders (48.6% vs 28.6%). Conclusion: Identi cation of response predictors, by quantitative analysis of perfusion parameters, might help clinicians in selection of patients who may bene t from targeted therapy, allowing for optimization of individualized treatment. Conference Suite II MC 3.2 Scienti c Session SS 9 Imaging update in upper GI pathologies and appendicitis SS 9.1 Diagnostic accuracy of esophageal functional MR in assessment of achalasia types S. Jovanovic, A. Simic, O. Skrobic, A. Djuric-Stefanovic; Belgrade/RS Purpose: Esophageal functional magnetic resonance (fMR) represents a dynamic test which is rarely applied in clinical practice. The aim of this study was to assess diagnostic value of fMR in patients with achalasia in comparison with manometric  ndings regarding 3 types of achalasia. Material and methods: Examination was performed on a 1.5T scanner using T2W SSFSE sequences speci ed protocol. Twenty- ve achalasia patients underwent functional testing while swallowing water. Esophageal dilation was measured on axial images and was de ned as a diameter >3.5 cm. Loss of peristalsis and motility dysfunction were determined as good, poor and absent. These results were compared to manometric  ndings, as a gold standard, and were divided according to 3 types of achalasia. Results: Manometric examination showed 6 patients with achalasia type 1, 18 with type 2 and one with type 3, while fMR indicated 7, 16 and 2 patients according to types, respectively. Overall accuracy of fMR was statistically similar to that of manometry (p=0.58). In six (24%) patients we found mismatch between types 1 and 2. Diagnostic performance of fMR was satisfactory, with sensitivity and speci city of 80% and 100%, respectively. Conclusion: Esophageal fMR was found to be a feasible and highly speci c dynamic technique, useful in determining types of achalasia and possibly clinically signi cant, regarding the outcomes of therapy. SS 9.2 The potential usefulness of MDCT in diagnosis of acute appendicitis in patients with atypical clinical presentation and to compare findings S. Merola; Narbonne/FR Purpose: To evaluate both the impact usefulness of MDCT in diagnosis of acute appendicitis (AA) in patients with atypical clinical presentation. Material and methods: This retrospective study included 138 consecutive patients (66 males; 72 females; age 54±17.4 years; range 18-90 years) with atypical clinical features. Histopathology results were available in patients who underwent surgery immediately after the MDCT scan. Results: Evaluation of MDCT scans was feasible in all patients. AA was diagnosed in 64 (46.4%) patients on MDCT using the de ned signs of appendicitis. 78/138 (56.5%) patients underwent emergency surgery (including all MDCTpositive patients) immediately after the diagnosis. In these cases, histopathology con rmed the diagnosis of AA in 58/78 (74.4%) patients. The three remaining MDCT-positive patients (4.3%) were false-positive with a  nal diagnosis of perforated diverticulitis of the sigmoid colon. In those patients, the appendix could not be identi ed retrospectively, because of abscess formation in the RLQ. In the remaining 14/78 patients (17.9%) who underwent surgery, ischemic colitis was diagnosed on MDCT in 10 patients (10.2%), and acute cholecystitis in 8 patients (7.7%) with histopathologically con rmation, respectively. Among the remaining patients, who did not undergo surgery (60/138), colitis was diagnosed on MDCT (n=10), urolithiasis (n=6), pyelonephritis (n=4), pancreatitis (n=4), and MDCT was unremarkable (n=36). Conclusion: MDCT usefulness has a fundamental impact in clinically equivocal cases of acute appendicitis. SS 9.3 Significance of timed barium esophagography in evaluation of laparoscopic myotomy for achalasia S. Jovanovic, A. Djuric-Stefanovic, O. Skrobic, N. Ivanovic, D. Masulovic, A. Simic; Belgrade/RS Purpose: Laparoscopic Heller myotomy (LHM) represents therapy of choice for patients with achalasia, providing excellent long-term outcomes. Aim of this study is to access signi cance of timed barium esophagography (TBE) in evaluation of esophageal emptying before and after LHM. Material and methods: Fifty-one patients with achalasia, con rmed by manometric studies, underwent TBE which was performed by swallowing 250 ml of low-density barium sulfate. Radiographic plane upright frontal  lms were performed 1, 2 and 5 min after ingestion. In all patients a LHM was done, and on the second postopertive day control TBE was obtained in the manner described above. Premyotomy and postmyotomy height and width of the barium column were compared. Results: At 1, 2, and 5 minutes before surgery, median barium column height was: 17.4±7.4 cm, 15.9±6.2 cm, and 13.9±6.2 cm; median barium column width was 5±1.5 cm, 4.7±1.6 cm, and 4.5±1.8 cm, respectively. LHM reduced these values to 7±4.6 cm, 5.8±4.2 cm, and 3.7±3.4 cm and to 2.9 ±1.3 cm, 2.6±1.3 cm, and 2.4±1.4 cm, respectively. All correlated diameters before and after myotomy indicated, in all three periods of time, the quantitative estimates of emptying as excellent (p value <0.01). Conclusion: TBE is a simple, useful, low-cost and reproducible technique. The quantitative assessment based on measurements of the barium column is an accurate and bene cial method, which estimates esophageal emptying success of LHD at short-term outcomes. SS 9.4 Evaluating response of locally advanced gastric adenocarcinoma to neoadjuvant chemotherapy using intravoxel incoherent motion MRI: preliminary results Y. Zhu, L. Jiang, Y. Li; Beijing/CN Purpose: To investigate the value of IVIM DW-MRI in evaluating the response to neoadjuvant chemotherapy (NCT) in locally advanced gastric adenocarcinoma (LAGA). Material and methods: Forty-two stage II–IVa LAGA patients diagnosed between 2014 and 2016 in the National Cancer Center of China were selected. All patients received 3-6 cycles of SOX NCT, and underwent two IVIM DW-MRI studies using 10 different b values (b=0, 10, 20, 50, 100, 200, 400, 600, 800, 1200 s/mm2) on a 3.0-Tesla MRI scanner (GE Discovery MR750 with an 8-channel CTL Target Array Coil): a baseline scan before therapy and a posttreatment scan within 2 weeks after  nished NCT. Diffusion coef cient (D), perfusion fraction (f) and pseudo-diffusion coef cient (D *) maps were calculated from the bi-exponential model. IVIM parameters (D, D*, and f) of LAGC were measured by region-of-interest (ROI) methods using the FuncTool on GE AW4.6 workstation. All patients received radical resection within 2 weeks after the second examination. According to the Mandard pathologic tumor regression grade (TRG), subjects were divided into responders (TRG 1-3) and nonresponders (TRG 4, 5). The IVIM parameters before (pre-parameters) and after (post-parameters) NCT and their corresponding changes (Δparameters) between the two groups were compared using the Student’s t test or nonparametric test. The diagnostic performance of different parameters was judged by the receiver-operating characteristic curve (ROC) analysis. Results: Based on the Mandard TRG criteria after 4-6 cycles of NCT, 25 patients were categorized into the responder group whereas the other 17 patients were considered nonresponders. The D value was signi cantly higher after treatment and the f value was signi cantly lower (all P < 0.05). In contrast, D* value was only slightly lower after treatment. Compared with nonresponders, a notably higher post-D value, ΔD and Δf were observed in responders (all P < 0.05), but no signi cant change other parameters among the 2 groups (P > 0.05). The ROC curve analysis indicated that the cutoff of ΔD value in best predicting TRG was 0.42×10-3 mm2/s, and the corresponding AUC, sensitivity, and speci city were 0.841, 66.7%, and 100.0%, respectively. Conclusion: IVIM-derived parameters, especially the D and f value, showed potential value in the prediction and response monitoring to neoadjuvant chemotherapy in LAGA. SS 9.5 Evaluation of gastroeosophageal junction in hiatal hernia with MDCT M. Koçak1, S. Gürel2, Z. Cogun 2, S.G. Gür2, N. engül 2, Y. Karagöz3; 1Mu/TR, 2Bolu/TR, 3Sivas/TR Purpose: Our aim is to evaluate the relation between MDCT measurements of His angle, hiatus area, crural thickness and hiatal hernia. Material and methods: Between February 2010 and February 2016, patients who had upper gastrointestinal system endoscopy and MDCT were searched from HIS. Two radiologists measured crural thickness, His angle and hiatus area on CT images independently in different sessions. Descriptive statistics, Student’s  t  (p<0.05), Mann–Whitney  U  and Pearson corrrelation tests were used for demographics, measurements in patient and control groups and interobserver variability, respectively. Results: Eighty-six (patient group: 42, control group: 44) of 93 patients had both endoscopy and CT. There was signi cant difference in His angle and hiatus area between two groups (reader 1: p=0.007, p<0.0001; reader 2: p=0.021, p=0.014), respectively. There was weak positive correlation for His angle in both groups, weak positive correlation in patient and high positive correlation in control group for hiatus area between readers. Although there was not signi cant difference in crural thicknesses between two groups, there was high positive correlation in crural thicknesses at celiac level between readers. Conclusion: Hiatus area and His angle are the main affected parameters in hiatal hernia. Hiatus area is the most powerful criteria in interobserver agreement that could easily take place in routine preoperative CT reports of hiatal hernia patients for the purposes of surgery management and outcome prediction. SS 9.6 Diffusion-weighted MRI in the assessment of response of gastric cancer to neoadjuvant therapy: correlation of the ADC values with tumor regression grade Y. Zhu, L. Jiang, Y. Li; Beijing/CN Purpose: To investigate the value of diffusion-weighted (DW) MRI in response assessment after neoadjuvant chemotherapy (NCT) in patients with locally advanced gastric cancer (LAGC). Material and methods: 40 patients with LAGC underwent respiratory gated DWI with b=0 and 800 s/mm2 on a 3.0-Tesla MRI scanner before starting therapy and after NCT. All patients underwent radical resection in 2 weeks after the second examination; surgical pathologic tumor regression grade (TRG) represented the reference standard. Subjects were divided into responders and nonresponders according to the TRG. ADC value before (pre-ADC) and after (post-ADC) NCT and their corresponding change (ΔADC) between the two groups were compared using the Student t test. The diagnostic performance of different parameters was judged by the receiver-operating characteristic (ROC) curve analysis. Results: Based on Mandard TRG criteria after 4-6 cycles of NCT, 25 patients were categorized into the responder group whereas the other 16 patients were considered nonresponders.The ADC value was signi cantly higher after treatment. ΔADC value was notably higher in responders compared with nonresponders, but no signi cant change in other parameters among the 2 groups. The ROC curve analysis indicated that the cutoff of ΔADC value in best predicting tumor NCT response was 0.25×10-3  mm2/s, and the corresponding AUC, sensitivity, and speci city were 0.770, 70.8%, and 81.2%, respectively. Conclusion: The ADC value showed potential value in the prediction and response monitoring to NCT in LAGC. SS 9.7 Non-enhanced Fast-MRI for radiological evaluation of acute appendicitis H. Goessmann, L.M. Dendl, B. Pregler, M. Scherer, S. Opitz, A.G. Schreyer; Regensburg/DE Purpose: Evaluation of a fast, non-enhanced and sequence-reduced MRI (Fast-MRI) without the use of oral, rectal or intravenous contrast-medium regarding diagnostic accuracy in patients with suspected acute appendicitis. Material and methods: 47 consecutive patients with suspected acute appendicitis in a tertiary care hospital were enrolled in this study. In addition to the routine workup (clinical examination and laboratory  ndings) a Fast-MRI (duration=12 min) with an orienting T2 Haste and DWI (b=0; 600; 1000) was performed. A diffusion restriction of the appendix was interpreted as in®ammation. The results of the MRI were compared to the clinical course or the intraoperative  ndings. Results: 25 of the 47 patients underwent surgery. Among those 16 diffusion restrictions and 7 normal DWIs were found. Two examinations were inconclusive. 14 of the 16 diffusion-restricted appendices showed an acute in®ammation intraoperatively. The other 2 had malignant  ndings (appendix and coecum carcinoma). 5 of the 7 not restricted appendices showed no signs of in®ammation intraoperatively. All of the 22 patients, who were treated conservatively, had a normal  nding in the MRI. Sensitivity as well as the PPV was 87.5%, while speci city and NPV were 93.1%, respectively. Conclusion: In this prospective study, Fast-MRI proved to be a quick and radiation-free option to rule out or con rm an acute appendicitis with a high degree of certainty. SS 9.8 Diagnostic performance of CT-arterial phase in assessment of decreased small bowel wall enhancement as a sign of ischemia in adhesive small bowel obstruction patients: a comparative study with venous phase A. Dallongeville1, I. Millet2, W. Khaled1, I. Boulay1, M. Zins1; 1Paris/FR, 2Montpellier/FR Purpose: To compare diagnostic performance of CT-arterial vs. CT-venous phase, to assess decreased small bowell-wall enhancement (DBE) as a sign of ischemia in adhesive small bowell obstruction (ASBO). Material and methods: 59 patients (mean age, 73.3 years) explored by a triphasic CT (unenhanced, arterial and venous phases) with  nal diagnosis of ASBO were included. Two gastrointestinal radiologists performed two blinded, independent, and retrospective reviews of CT, for evaluating DBE. Read 1 included an unenhanced CT and CT-arterial phase images, and read 2, one month later, an unenhanced CT and CT-venous phase images. Reference standard for ischemia was proved by surgery. Diagnostic performances of DBE for ischemia were calculated for each reader and for consensual reading and compared between the two readings using McNemar rank tests. Kappa statistics were used to analyze interobserver agreement. Results: Ischemia was con rmed in 21 of 59 (35.6%) cases. There was no signi cant difference in interobserver agreement (kappa=0.62 and 0.61) for assessing DBE between the 2 readings. Global diagnostic performance for each reader was not signi cantly different between the 2 readings (p=0.11 and 0.86). After consensus, sensitivity, speci city, positive and negative predictive values were 81%, 74%, 63% and 87%; and 81%, 79%, 68% and 88%, without signi cant differences for read 1 and 2, respectively. Conclusion: CT-arterial phase does not improve interobserver agreement, nor the diagnostic performance for assessment of DBE as a sign of ischemia in ASBO. SS 9.9 Evaluation of acute appendicitis with dual-energy CT C. Topel, M.R. Onur, E. Unal, N.M. Aksu, A.D. Karaosmanoglu, E. Akpinar, M. Karcaaltincaba; Ankara/TR Purpose: To assess the utility of dual-energy computed tomography (DECT) in the diagnosis of acute appendicitis (AA). Material and methods: The DECT scans of consecutive 30 patients (12 male, 14 female) with AA and 30 consecutive patients (12 male, 14 female) with normal appendix vermiformis (AV) were recruited to this study. The maximum diameter of AV as well as the density of most compressed and in®amed site of AV at 80 kVp, 140 kVp, virtual non-contrast (VNC), iodine overlay, mixed, and monoenergetic (40, 50, 60, 70, 80, 90, 100, 190 keV) images were quanti ed. Results: The attenuation values of in®amed AVs were higher than that of normal AVs at 80 kVp, 140 kVp, VNC, iodine overlay, mixed images and all virtual monochromatic energy levels (p<0.001). Sensitivity and speci city values were calculated for certain cut-off attenuation values as ranging from 60% to 96.7%. 80 kVp images yielded the highest diagnostic accuracy with AUC of 0.996 following maximum diameter with AUC of 1 (p<0.001). 70 keV and 80 keV energy levels provided the highest diagnostic accuracies with AUC of 0.958 and 0.934, respectively. Conclusion: AA can be more easily detected in iodine overlay, low kVp and low-energy monochromatic images of DECT due to increased attenuation values at certain energy levels. The 80 kVp and virtual energy monochromatic images at 70 keV and 80 keV energy levels yield the highest diagnostic accuracies in the setting of AA. SS 9.10 A new strategy to maximize diagnostic accuracy of sonography in the patient with suspected appendicitis D.A. Castro1, R. Regan2, W. Hopman2, M. Kolar2, D.A. Soboleski2; 1Toronto, ON/CA, 2Kingston, ON/CA Purpose: To provide evidence supporting the triaging of ER patients sent to radiology with suspicion of appendicitis to the sonographers with history of success in identifying the appendix. Recent studies have demonstrated wide performance differences among imagers during competency assessment despite their level of training, suggesting a perception plateau for image interpretation. Material and methods: All patients sent to ultrasound over a year period with concern of appendicitis were included. Outcomes were gathered. Patients were scanned by 1 of 15 sonographers with experience of 2–33 years or by a resident. Chi-square tests and one-way ANOVA were used to test the associations of ultrasound results with sonographer’s years of experience, length of exam, patient age and the impact on patient care. Results: Of 455 patients, the appendix was not visualized in 52% of cases. Non-visualization of the appendix per sonographer ranged from 5% up to 69%. Subsequent CT was performed in 36% of these patients with 83% having normal results. The sonographer’s success in visualizing the normal appendix ranged from 8% to 76% with an average of 24%. There was no correlation between sonographer’s years of experience, time spent scanning or resident year of training with success of visualizing the normal appendix. Conclusion: An individual sonographer’s perception skill plays signi cant role in the ability to visualize the appendix, which affects CT utilization and hospital costs and impacts patient care. Alexandra Trianti Hall Scienti c Session SS 10 Best rated papers on colorectal cancer evaluation SS 10.1 Response to neoadjuvant therapy in locally advanced rectal cancer: assessment combining standardized index of shape of dynamic contrast-enhanced MRI and intravoxel incoherent motion method of diffusionweighted MRI R. Fusco, M. Petrillo, V. Granata, A. Petrillo; Naples/IT Purpose: To evaluate MRI for neo-adjuvant therapy response in locally advanced rectal cancer (LARC) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weigthed imaging (DWI). Material and methods: 40 patients with LARC underwent MR examination before and after pCRT. SIS, apparent diffusion coef cient (ADC), tissue diffusion (Dt), pseudodiffusion (Dp) and perfusion fraction (f) were calculated for each patient before and after pCRT. Percentage changes were evaluated. Non-parametric sample tests, receiver operating characteristic curve (ROC) and diagnostic performance were performed. Results: 23 Patients were classi ed as responders (TRG≤2) and 17 as nonresponders (TRG>3). Statistically signi cant differences in SIS and ADC percentage change median values between responders and non-responders patients were found. The best parameters to discriminate responder by non-responders patients (ROC analysis) were ΔSIS and ΔADC with an accuracy of 85% and 83% (cut-off value of 5.2% and 21.4%, respectively) while to discriminate pathological complete response were Δf and ΔDp with an accuracy of 80% and 85% (cut-off value of 64.0% and 70.6%, respectively). Combining ΔSIS and ΔDt an accuracy of 95% and 93% was obtained to discriminate responder from non-responder patients and to assess pathological complete response. Conclusion: SIS is a promising DCE-MRI angiogenic biomarker useful to assess preoperative treatment response directing surgery for more or less conservative treatment. If combining ΔSIS and pure tissue diffusion coef cient change (ΔDt), a further increase of accuracy could be obtained. SS 10.2 Performance of texture analysis in predicting tumoural response to neoadjuvant chemoradiotherapy in rectal cancer patients studied with 3T MR M. Zerunian, D. Bellini, M. Rengo, D. Caruso, F. Rivosecchi, A. Laghi; Latina/IT Purpose: To determine the performance of texture analysis (TA) in the prediction of tumoral response in colon rectal cancer (CRC) patients. Material and methods: We prospectively enrolled 40 consecutive CRC patients, who underwent pretreatment, midtreatment and posttreatment 3T MRI. A region of interest was drawn manually around the tumor on unenhanced T2-weighted images and analyzed using TA (TexRAD), evaluating texture parameters (skewness, kurtosis). After CRT, all patients underwent complete surgical resection and the surgical specimen served as the gold standard. Receiver operating characteristic (ROC) curve analysis was performed to assess the discriminatory power of each quantitative parameter to predict complete response. Results: Thirteen patients showed pathological complete response (pCR). Twenty-two patients showed partial response (PR) and  ve patients were nonresponders (NRs). pCR patients showed a signi cantly lower kurtosis at preCRT analysis compared to PR+NR subgroup (P=0.01). During-treatment kurtosis was signi cantly higher in pCR compared to PR+NR (P=0.043). PR+NR showed a little change in kurtosis between pre-CRT and during-CRT compared to pCR (P = 0.039). The optimal cutoff value for pretreatment kurtosis was 0.17, resulting a sensitivity and speci city for pCR prediction of 100% and 79.4%, respectively. Conclusion: TA from T2w images can potentially have an important role as imaging biomarkers of tumoral response to neoadjuvant CRT in rectal cancer. SS 10.3 Evaluation of locally advanced rectal cancer response to radiochemotherapy: detailed multiparametric positron emission tomography-MR correlation with histopathology M. Cerny, V. Dunet, C. Rebecchini, J. Prior, C. Sempoux, S. Schmidt Kobbe; Lausanne/CH Purpose: To prospectively evaluate the histological signi cance of apparent diffusion coef cient (ADC) and  18F-FDG PET/CT parameters’ changes in locally advanced rectal cancer (LARC) after radiochemotherapy (RCT). Material and methods: Twenty-one patients (age 61±11y, male 13) with untreated LARC underwent  18F-FDG PET/CT and 1.5-T DW-MRI (b=0, 600 s/ mm2), before and after RCT, followed by surgery. For both datasets (pre- and post-RCT), two readers measured the tumor SUVmax, SUVmean, ADCmin and ADCmean, and their respective differences (ΔSUVmax, ΔSUVmean, ΔADCmin, ΔADCmean) on the whole tumor. Tumor regression grade (TRG), residual percentage of tumor cells and  brosis were estimated by two pathologists in consensus. Relationships between all these parameters were assessed on stepwise multivariate regression analysis. Results: Nineteen LARCs could be analyzed both on  18F-FDG PET/CT and DW-MR images. After RCT, tumor SUVmax and SUVmean signi cantly decreased from 21.3±8.9 to 9.3±5.5 g/mL (p=0.0002) and from 12.3±5.1 to 5.4±3.1 g/mL (p=0.0002), respectively, while ADCmin and ADCmean signi cantly increased from 396±269 to 573±313x10-6  mm2/s (p=0.014) and from 1159±212 to 1355±194x10-6 mm2/s (p=0.0008), respectively. On multivariate regression analysis, post-RCT tumor SUVmean was independently correlated with TRG (b=0.73, p<0.001) and with the percentage of residual tumor cells (b=0.76, p<0.001), while ΔADCmean (b=0.38, p=0.008) was independently correlated with the percentage of  brosis. Conclusion: Post-RCT tumor SUVmean and ΔADCmean are complementary imaging parameters to, respectively, evaluate residual tumor burden and microenvironment changes after RCT in LARC. SS 10.4 Prevalence of post-investigation colorectal cancer (“interval cancer”) after computed tomographic colonography: a systematic review A. Obaro1, A. Plumb2, T. Fanshawe3, U.S. Torres4, R. Baldwin-Cleland1, S. Halligan2, D. Burling1; 1Harrow/GB, 2London/GB, 3Oxford/GB, 4Sâo Paulo/BR Purpose: To establish the currently unknown post-investigation colorectal cancer (PICRC), or “interval cancer”, rate after CTC by systematic review. Material and methods: Primary studies reporting PICRC (diagnosis of cancer within 5 years of negative CTC), or suf cient data to calculate it, were identi ed from Pubmed, Embase and the Cochrane Register by systematic search. Peer-reviewed studies published after 1994, and with over 12 months followup, were selected and data extracted by two independent authors. The PICRC rate was pooled across studies using random-effects meta-analysis. Following World Endoscopy Organization recommendations, PICRC rates were calculated using (a) number of cancers identi ed and (b) number of CTCs completed as denominators. The study is registered (PROSPERO:CRD42016046838) and adhered to PRISMA recommendations. Results: 14 studies met the inclusion criteria. These included 34,003 patients (age 18-96 years; 57% female) undergoing 19,358 CTCs from March 2002 to May 2015. Overall patient population was 34% symptomatic only (11438/34003), 19% screening only (6690/34003) and 47% mixed (15875/34003). Pooled across studies, 688 cancers were detected and 30 were missed, at an average length of follow-up of 3 years, giving a PICRC rate of 30/688=4.4%. When using the number of CTCs as the denominator, PICRC rate was 30/19358=0.5%. Conclusion: Using the World Endoscopy Organization de nition, the PICRC rate after CTC is approximately 4.4%, lower than published rates for optical colonoscopy. These data will help rationalize follow-up of patients with initially negative CTC. SS 10.5 Diagnostic accuracy of MDCT imaging in assessment of mesorectal fascia invasion in rectal cancer: comparison study with standard MRI S.G. Drago, D. Ippolito, C. Talei Franzesi, D. Fior, S. Sironi; Monza/IT Purpose: To assess the diagnostic accuracy of MDCT images with multiplanar reconstructions (MPR) in comparison with conventional MRI, in identifying mesorectal fascia (MRF) invasion in rectal cancer patients. Material and methods: One hundred patients with biopsy-proven primary rectal adenocarcinoma referred for thoracic and abdominal CT staging were enrolled in this study. The contrast-enhanced MDCT scans were performed on a 256 (ICT, Philips) row scanner with the following acquisition parameters: tube voltage 120 KV and tube current 150-300 mAs. Multiplanar CT reconstructions were performed and imaging data were reviewed as axial and as MPR images, along with rectal tumour axis. MR study, performed on 1.5 T magnet included standard multiplanar T2-weighted and axial T1-weighted sequences. The MRF involvement was assessed on axial and MPR images independently and compared with MRI imaging  nding. Diagnostic accuracy of both modalities was compared and statistically analyzed. Results: Multidetector-row CT images agreed with those of MRI, obtaining CT axial images sensitivity and speci city of 80.4% and 75%, PPV of 80.4%, NPV 75% and accuracy of 78%. Using MPR the sensitivity increased up to 88% and speci city to 87%, PPV was 90%, NPV 85.36% and accuracy of 88%. Conclusion: New-generation CT scanners, using high-resolution MPR images along tumor axis, can be considered a complementary technique for loco-regional and whole body staging in rectal cancer patients, especially in those with MRI contraindications. Scienti c Session SS 11 New insights into pancreatic abnormalities and techniques SS 11.1 Definition of age-dependent reference values for diameter of the common bile duct and pancreatic duct on MRCP from a population-based cohort study F. Kasprowicz1, G. Beyer2, M.-L. Kromrey1, J. Mayerle2, M. Lerch1, J.-P. Kühn1; 1Greifswald/DE, 2Munich/DE Purpose: To de ne new reference values for diameters of pancreaticobiliary ducts on MRCP in the general population and to identify factors in®uencing duct size. Material and methods: Subjects were recruited from the general populationbased Study of Health in Pomerania (SHIP) and had whole body MRI + MRCP (1,5T MRI). Diameters of pancreatic duct (PD) and common bile duct (CBD) were measured on MRCP by an investigator blinded to other subject data. Results: 1385 subjects were initially scanned, 865 measured PDs and 938 CBDs were included for analysis. Subjects were excluded for missing data or evidence of pancreaticobiliary disease. Median age was 53y (21-89y) and 48.5% were female. The diameters increased with age (PD median (1st-3rd quartile), 20-29 years: 1.33mm (1.20–1.57), >70 years: 2.49mm (1.85–3.01); CBD median (1st-3rd quartile), 20-29 years: 4.53mm (3.87–5.17), >70 years: 6.50mm (5.10–8.23)) and the historic upper limit of normal of 3mm for PD and 7mm for CBD were exceeded by 11% and 18.2%, respectively. Subjects that underwent cholecystectomy presented with signi cantly increased diameter of CBD, but not PD (CBDw/oCCE: 5.30mm±1.893 vs. CBDw/CCE: 8.18mm±2.841, p<0.01; PDw/oCCE: 1.84mm±.778 vs. PDw/CCE: 2.06mm±.868, p>0.01). Conclusion: Up to 18% of healthy volunteers would have undergone diagnostic workup for enlarged CBD or PD above the current reference standard. The width of the pancreaticobiliary ducts increases in an age. An increase of the CBD after cholecystectomy can be observed, whereas the PD remains unaffected. SS 11.2 Clinical feasibility of breath-hold 3D MRCP with compressed sensing J.H. Yoon1, J.M. Lee1, S.M. Lee1, H.-J. Kang1, B. Kiefer2, Y. Son1, J.K. Han1; 1Seoul/KR, 2Erlangen/DE Purpose: To investigate clinical feasibility of breath-hold 3D MRCP using compressed sensing. Material and methods: This retrospective study was approved by institutional review board and the requirement of informed consent was waived. A total of 42 patients (M:F =25:17, mean age 59.4±14.9 years) who underwent conventional respiratory-triggered MRCP and breath-hold MRCP using a 3T scanner were included. Three board-certi ed radiologists independently reviewed both exams for bile duct and pancreatic duct visualization and overall image quality on a  ve-point scale, and image sharpness and background suppression on a four-point scale, with a higher score indicating better image quality. The results and acquisition time were compared using either the Wilcoxon signed-rank test or paired t test between the two MRCP exams as appropriate. Results: The acquisition time of breath-hold MRCP was 21 seconds, and that of respiratory-triggered MRCP was 5:30 seconds on average. Overall image quality was signi cantly higher in breath-hold MRCP than respiratory-triggered MRCP (3.98±0.88 vs. 3.49±1.24, P=0.013). Breath-hold MRCP showed higher image sharpness (3.21±0.87 vs. 3.78±0.40, P<0.0001) than respiratory-triggered MRCP, and there was no signi cant difference of background suppression between the two exams (3.42±0.54 vs. 3.38±0.54, P=0.696). For bile duct visualization, breath-hold MRCP showed signi cantly better demonstration of the common bile duct (4.71±0.75 vs. 4.31±0.94, P=0.001), cystic duct (3.55±1.33 vs. 3.08±1.33, P=0.021) and bilateral 1st  intrahepatic ducts (4.44±0.72 vs. 4.07±1.08, P=0.012 for right, 4.36±0.88 vs. 4.02±1.16, P=0.018 for left). There was no signi cant difference in pancreatic duct visualization between the two exams (3.71±1.21 for respiratory-triggered and 3.63±1.24, P=0.668). Conclusion: Breath-hold MRCP was able to provide comparable or superior image quality compared with conventional respiratory-triggered MRCP. The short acquisition time could contribute to improved MR work®ow. SS 11.3 CT description of pancreatic and peripancreatic collections in the first month of acute pancreatitis: an interobserver variability study using the revised Atlanta classification 2012 N. Badat1, I. Millet2, L. Corno1, W. Khaled1, S. Beranger1, I. Boulay1, M. Zins1; 1Paris/FR, 2Montpellier/FR Purpose: To assess the interobserver agreement of categorizing pancreatic and peripancreatic collections using the revised Atlanta classi cation (RAC) in the  rst month of acute pancreatitis (AP), and to correlate the type of collection with outcome. Material and methods: Among 131 consecutive patients hospitalized for 139 episodes of AP, 195 CTs performed within the  rst month, and presenting peripancreatic anomalies were analysed. The episodes of AP were classi ed into three degrees of severity according to the RAC: mild, moderately severe and severe. Two radiologists blinded to the clinical data restrospectively categorized the collections as acute peripancreatic ®uid collections (APFC) or acute necrotic collections (ANC), using the RAC criteria. Interobserver agreement was assessed using statistics, and compared according to the timing of the CTs. Results: Interobserver agreement to categorize peripancreatic collections was moderate (=0.45). This agreement did not increase with the timing of the CTs: was 0.51 before day 3, 0.36 between day 3 and day 7 and 0.53 after day 7. For the detection of parenchymal necrosis, the interobserver agreement was also moderate (=0.42). There was a tendency for less severity among patients with APFC compared with patients with ANC (p=0.06). Conclusion: The RAC shows a moderate interobserver agreement to categorize both peri- and intra-pancreatic collections. The type of collection occuring during the  rst month of an AP is associated with the severity of the pancreatitis. SS 11.4 Evaluation of extracellular volume fraction and T1 mapping for the diagnosis of chronic pancreatitis T. Tirkes, E. Cui, P.R. Territo, C. Lin, B.L. Bick, E.L. Fogel, F. Akisik; Indianapolis, IN/US Purpose: To determine if extracellular volume (ECV) fraction and T1 relaxation times can be useful diagnostic criteria for chronic pancreatitis (CP). Material and methods: Total of 122 patients were grouped into the normal (n=53), suspected (n=26) and de nite (n=43) CP cohorts based on enrollment criteria, which included history, clinical  ndings, endoscopic US, ERCP and MRCP results. T1 mapping was performed using dual ®ip angle (2° and 13°) gradient echo imaging technique on the same 3T scanner (TR: 3.87, TE: 1.32). T1 maps were acquired in the pre- and 5-minute delayed post-contrast phases and reconstructed with Siemens MapIt Software. ECV fraction was calculated using the formula ECV= [1–hematocrit] x ΔR1pancreas / ΔR1blood. Results: There was statistical signi cance between the average ECV fraction of the 3 groups; normal (0.27 ±0.08) and suspected (0.38 ±0.10, p=0.0009), normal and de nite (0.46 ±0.10, p<0.00001) and suspected and de nite (p=0.015) CP groups. Average T1 relaxation times also showed statistical signi cance between the normal (751±221 msec) and suspected CP group (1018 ±295 msec, p=0.01) and normal and de nite CP groups (1105 ±356 msec, p< 0.00001). ECV fraction >0.32 was 80% sensitive and 84% speci c for the diagnosis of suspected and de nitive CP (AUC= 0.88). Combined criteria of ECV fraction >0.30 and T1 >1000 msec showed 92% sensitivity and 71% speci city (AUC= 0.89). Conclusion: ECV fraction and T1 relaxation times can be useful imaging techniques to diagnose CP. SS 11.5 MRI features of paraduodenal pancreatitis and differential diagnosis with pancreatic adenocarcinoma E. Boninsegna, R. Negrelli, G. Tedesco, G.A. Zamboni, R. Manfredi, R. Pozzi Mucelli; Verona/IT Purpose: Paraduodenal pancreatitis (PDP) is an uncommon type of chronic pancreatitis affecting the “groove”, a region between the head of the pancreas and the duodenum. It presents common features with pancreatic adenocarcinoma (PA) and differential diagnosis could be dif cult. We evaluated its MRI aspects, to identify distinctive elements with PA. Material and methods: Fifty-six patients patients had been included; 28 were affected by PDP, 28 by PA; every condition was pathologically proven. For both groups we evaluated: size of the lesion, presence of cystic components, signal intensity on T1- and T2-weigthed images (WI), on DWI and after contrast medium administration, dilatation of hepatic duct and main pancreatic duct. Results: On T1-WI 18/28 (64.3%) PDP and 25/28 (89.3%) PA were hypointense to the healthy pancreas; on T2-WI 19/28 (67.9%) PDP were isointense and 18/28 (64.3%) PA were hyperintense (p>0.05). On DWI, 20/28 (71.4%) PDP were isointense and every PA was hyperintense (p<0.01). In the delayed phase post contrast administration 18/28 (64.3%) PDP were hyperintense and 14/28 (50%) PA were isointense (p<0.01). Cysts within the lesion were present in 24/28 (85.7%) PDP; 15/28 (53.6%) PA presented the “double duct” sign; 11/15 (73.3%) PDP presented calci cations within the lesion. PDP mean volume was 59.9 cm3, PA volume 10.7 cm3 (p<0.01). Conclusion: PDP features useful for the differential diagnosis with PA are: presence of cysts and calci cations, normal ADC values, high signal intensity on delayed phases and greater dimensions. SS 11.6 Incidence, prevalence and pancreatic-related mortality of pancreatic cysts in a population-based study M.-L. Kromrey1, R. Bülow1, C. Paperlein1, T. Ittermann1, M. Lerch1, J. Mayerle2, J.-P. Kühn1; 1Greifswald/DE, 2Munich/DE Purpose: To analyze the prevalence, incidence and clinical relevance of pancreatic cysts detected as incidental  nding in a population-based longitudinal study. Material and methods: 1,077 participants (521 men, mean age 55.8±12.8 years) underwent T2-weighted MRCP at baseline in a population-based study. 676 subjects received a 5-year follow-up, mortality follow-up was performed after 6 years. MRCP was analyzed for pancreatic cysts with a diameter >2 mm. The prevalence and incidence of pancreatic cysts were assessed in association to age, gender and suspected risk factors (BMI, smoking, lipase, triglycerides, total cholesterol, HbA1c, alcohol, systolic blood pressure). Results: At baseline pancreatic cysts were detected with a prevalence of 49.1% (total 1,681 cysts in 494 subjects), with an average number of 3.9 (CI 95% 3.2; 4.5) cysts per subject. Prevalence (p<0.001), number (p=0.001) and maximum size (p<0.001) of pancreatic cysts increased signi cantly with age. Concerning risk factors, a signi cant association was seen between cyst development and BMI, triglyceride level and total cholesterol. The 5-year followup revealed an incidence of 12.9% newly detected pancreatic cysts. 35.4% of the subjects initially harboring pancreatic cysts, showed an increase in number and/or maximum cyst size. No participant died of pancreatic diseases within mortality follow-up. Conclusion: The prevalence of pancreatic cysts in general population is unexpectedly high and increases with age. Prospective follow-up data in a population-based setting suggests that most pancreatic cysts are harmless incidental  ndings. SS 11.7 Pancreaticoduodenal artery aneurysms: evaluation of frequency and possible etiological associations G. Caruana, R. Cannella, D. Picone, D. Giambelluca, S. Pellegrino, G. Salvaggio, E. Grassedonio, G. Lo Re, R. Lagalla; Palermo/IT Purpose: To evaluate the prevalence of pancreaticoduodenal artery (PDA) aneurysms, and to de ne possible etiological associations. Material and methods: We conducted a record-based cross-sectional study at our institution, collecting radiological reports of abdominal contrast-enhanced CT scans of 12,736 patients, performed from January 2012 until December 2016. Reports were reviewed searching for visceral aneurysms. Then the corresponding CT images were evaluated, selecting only studies showing PDA aneurysms. Results: PDA aneurysms were identi ed in 7 patients (1 male and 6 females). The mean age was 60.7 years (range 30-81 years). The mean aneurysm size was 2.0 cm (range 1.1-3.5 cm). One patient had a gastroduodenal artery (GDA) aneurysm associated. Six patients (86%) had severe stenosis or occlusion of the celiac artery, most likely due to compression by the median arcuate ligament. Three patients (43%) had portal hypertension signs. Six patients (86%) had enlargement of at least one PDA; 6 patients (86%) had enlargement of GDA; 1 patient (14%) had enlargement of dorsal/transverse pancreatic artery. We calculated a prevalence of PDA aneurysms of 0.055% (55 /100,000 patients). Conclusion: The prevalence of PDA aneurysms found in our study (55/100,000) is higher than that reported in the current literature (1-2/100,000) derived from autopsy studies. We found an association with celiac artery compression in 86% of patients, in disagreement with a literature frequency of 50-60%, most likely due to the low number of cases studied. SS 11.8 Automatic segmentation of pancreatic adenocarcinoma based on supervised learning methods N. Papanikolaou1, I. Serafeimidis2, E. Di Campli1, N. Kartalis3, K. Marias2, C. Matos1; 1Lisbon/PT, 2Heraklion/GR, 3Stockholm/SE Purpose: To develop and validate a supervised learning model for automatic segmentation of pancreatic adenocarcinoma based on texture features extracted from diffusion-weighted MR images. Material and methods: 14 patients with pancreatic adenocarcinoma underwent MRI examination on a 1.5T system. B1000 DWI images were used to extract texture features. An expert radiologist manually traced regions of interest separately for pancreatic cancer and non-cancerous tissue. 11 Haralick texture features were extracted on a pixel by pixel basis. 4 different models based on Naïve Bays, J48, k-NN and Random Forests were trained using 80% of the data with a 10-fold cross-validation method. The number of features were reduced to 100 from 310 by means of 4 feature selection methods (correlation between features and with classes, entropy and relief). Testing was based on 20% of the data that were not included in the training phase. Area under the receiver operating characteristic curve (AUROC) was calculated and compared between all 4 models. Results: Random forest algorithm provided with the highest AUROC (1.00, F value: 0.99) while the k-NN resulted in the second highest AUROC (0.992, F value: 0.995). Differences between RF and k-NN in AUROC did not reach statistical signi cance (p=0.76). Conclusion: Automatic segmentation of pancreatic cancer is feasible using texture features from b1000 diffusion images in combination with a random forest model. SS 11.9 Role of the pre-operative CT scan in predicting postoperative pancreatic fistula after pancreaticoduodenectomy A. Ng1, E. Neo2, K. Tew2, H. Kanhere2; 1Southport, QLD/AU, 2Woodville South, SA/AU Purpose: Pancreaticoduodenectomy (PD) is the mainstay operative treatment of pancreatic head and periampullary tumours. Despite advances in operative technique and centralisation of PD to high-volume centres, peri-operative morbidity remains high. Postoperative pancreatic  stula (POPF) is a major contributor to both mortality and morbidity. The aim of this study was to assess the role of the pre-operative CT scan in assessing for pancreatic duct location and size, and fatty pancreatic in ltration and their association with POPF. Material and methods: 65 patients who underwent PD were retrospectively identi ed from a database at an Adelaide tertiary hospital. Age, sex and POPF were obtained from the patients’ records. Pancreatic diameter and position, and pancreatic tissue attenuation was measured from pre-operative CT scans. Results: 18 of 65 (28%) patients who underwent PD had POPF. Age, sex, pancreatic tissue attenuation and pancreatic duct location were not signi cantly associated with POPF. POPF was signi cantly associated with pancreatic duct size (p = 0.0006). POPF rates were signi cantly higher when duct size was <3mm (15 of 29, 52%) compared to when duct size was >3mm (3 of 36, 8%), p= 0.0001. Conclusion: Our study demonstrated that smaller pancreatic duct size is predictive of POPF. Acquisition of pancreatic duct size on pre-operative CT scan may aid surgeons in tailoring surgical management and assessing the patient’s risk of POPF after PD. SS 11.10 CT texture analysis of non-functioning endocrine tumors of pancreas A. Mazzaro, M. Chincarini, E. Boninsegna, G.A. Zamboni, R. Pozzi Mucelli; Verona/IT Purpose: To compare the CT texture analysis features of non-functioning endocrine tumors of the pancreas across tumor grade groups. Material and methods: We reviewed the MDCTs of 154 pNETs, and from these selected 45 patients for whom DICOM data of non-contrast CT were available. Two readers in consensus performed texture analysis of each lesion on the most representative slice with MaZda software, using contrast-enhanced images as a reference to trace the ROIs. First-order statistics (mean intensity, variance, skewness and kurtosis) data were extracted. The ANOVA test was used for analysis. Results: Mean intensity was 122 for G1 tumors, 121 for G2 tumors and 121 for G3 tumors, with no signi cant difference between groups. Mean variance was 165 for G1 tumors, 169 for G2 tumors and 128 for G3 tumors, with no signi cant difference between groups. Mean skewness was -0.13 for G1 tumors, -0.066 for G2 tumors and -0.25 for G3 tumors, with no signi cant difference between groups. Mean skewness was 0.52 for G1 tumors, 0.22 for G2 tumors and 0.89 for G3 tumors, with no signi cant difference between groups. Conclusion: First-order statistics from CT texture analysis do not appear to be useful in the noninvasive grading of nonfunctioning pNETs. Conference Suite II MC 3 Scienti c Session SS 12 Primary malignant liver lesions SS 12.1 Hyperintense nodule at hepatobiliary phase arising within hypovascular hypointense nodule: a different paradigm of “nodule in nodule” appearance? R. Cannella, A. Calandra, M. Midiri, G. Brancatelli; Palermo/IT Purpose: To retrospectively evaluate the outcomes and imaging features associated with occurrence of hyperintense nodule at hepatobiliary phase (HBP) arising within hypovascular hypointense nodule at gadoxetic acid-enhanced MRI in patients with chronic liver disease. Material and methods: We included 11 patients (7 males and 4 females, mean age 73 years, range 63-83 years) who had a hyperintense nodule at HBP arising within a larger hypovascular hypointense nodule at gadoxetic acid-enhanced MRI. We evaluated size and signal intensity of nodules in all sequences. Serial MR studies were available in 6 patients. Results: Mean diameter of the “outer” hypovascular hypointense nodule was 2.3 cm (range 1.2-4.5 cm) while diameter of the “inner” hyperintense nodule at HBP was 1.1 cm (range 0.6-1.3 cm). All intranodular foci were hyperintense at HPB and showed a typical pattern for HCC with enhancement at hepatic arterial phase and wash-out at portal-venous phase (n=7), wash-out only (n=3) and enhancement with no wash-out (n=1). In those six patients with serial MR examinations available, we observed either appearance of hyperintense nodule at HBP within hypovascular hypointense nodule (n=3) or appearance of hypervascularity at HAP of hyperintense nodules at HBP (n=3). Conclusion: Hypovascular hypointense nodules are at risk for development of hyperintense nodule at HBP, likely representing HCC. SS 12.2 Can MRI do better than EASL criteria for the diagnosis of small HCC? J.-B. Coty1, J. Lebigot1, M. Esvan2, J. Lonjon3, O. Seror4, A. Rode5, V. Vilgrain6, C. Aubé1; 1Angers/FR, 2Paris/FR, 3Montpellier/FR, 4Bondy/FR, 5Lyon/FR, 6Clichy/FR Purpose: To assess the performance of MRI for the diagnosis of small HCC, especially for nodules which do not ful ll the European Association for the Study of the Liver (EASL) criteria. Material and methods: 364 cirrhotic patients underwent liver MRI for nodules <30 mm suspected of HCC. For each nodule the following were recorded: signal in T1, T2 and diffusion-weighted imaging, intra-lesional fat, peritumoral capsule and enhancement pattern. The diagnostic performance of each sign and of different sign associations was calculated using a composite algorithm as reference. Results: 300 nodules of 10-20 mm and 193 nodules of 20-30 mm have been retained for the analysis. The EASL criteria were the most effective for HCC diagnosis: sensitivity (Se)=71.7%; speci city (Sp)=80.0% for the 10-20 mm nodules and Se=73.4%; Sp=97.1% for the 20-30 mm nodules. For the 10-20 mm nodules that did not display EASL criteria, hyperintensity on diffusionweighted imaging was the most ef cient sign for the diagnosis of HCC: 1) for nodules without arterial enhancement: Se=71.4% and Sp=75%; 2) for nodules without wash-out on portal or delayed phases: Se=65.2% and Sp=66%; 3) for nodules without arterial enhancement, nor wash-out on portal or delayed phases: Se=66.7%; Sp=91.7%. Conclusion: In MRI, EASL criteria remain the best criteria for the diagnosis of small HCC. However, the use of the different MRI sequences allows close performances for the nodules that do not ful ll the EASL criteria. SS 12.3 Predicting HCC patient survival from diffusion-weighted MRI images using a convolutional neural network G. Kaissis, P. Christ, F. Ettlinger, S. Schlecht, F. Grün, A. Valentinitsch, E.J. Rummeny, B. Menze, R. Braren; Munich/DE Purpose: Computer-aided analysis techniques allow medical image feature extraction beyond the capabilities of the human eye. Non-invasive differentiation of tumor subtypes in HCC would enable pre-therapeutic patient strati cation and the systematic testing of novel therapeutic strategies. Material and methods: Histopathologically proven HCC bearing patients underwent 1.5 T DW-MRI. A cascaded fully convolutional neural network was applied to segment liver and tumor lesions. A 5-fold cross-validation was applied. As ground truth, manual segmentation was performed by experienced radiologists using the software TurtleSeg. To predict the survival rate of HCC tumor patients we calculated different features using the detected and segmented tumor lesions applied in the ADC image sequences. Kaplan–Meier survival analysis was performed for classical histogram features, Haralick features and the developed CNN (3D SurvivalNet). Results: The trained model was highly sensitive in recognizing HCC lesions with a sensitivity of 91.1%. SurvivalNet achieved higher scores compared to handcrafted features with an accuracy, precision and sensitivity of 68%, 69% and 68%, respectively. Conclusion: With the growing appreciation of tumor heterogeneity as a major obstacle to treatment response, more sophisticated image analysis algorithms are required. We present a fully automatic framework to predict survival times of HCC patients. This approach based on fully convolutional and 3D convolutional neural networks outperformed state-of-the art handcrafted features. This work may have potential applications in HCC treatment planning. SS 12.4 Transarterial radioembolization following chemoembolization for unresectable HCC: response based on apparent diffusion coefficient change is an independent predictor for survival E. Klompenhouwer1, R.C. Dresen2, C. Verslype2, A. Van Laenen2, V. Vandecaveye2, G.A. Maleux2; 1Amsterdam/NL, 2Leuven/BE Purpose: There is sparse data on the use of diffusion-weighted imaging (DWI) in treatment response assessment of intra-arterial therapies in patients with HCC. The aim of the study is to evaluate whether ADC change at DWI after radioembolization (TARE) is a predictor for survival, in patients who have previously undergone chemoembolization (TACE) for HCC. Material and methods: We identi ed all patients who received one or more sessions of TACE prior to TARE for HCC in the period 2007-2016. Response on MRI was determined by modi ed RECIST (mRECIST) and ADC change relative to pre-TARE imaging (ADC ratio). Kaplan–Meier and log-rank tests were used to correlate the response, disease and treatment variables to survival. Multivariable Cox regression models were used to correct for confounders. Results: A total of 29 patients were included. Radiologic response rates based on mRECIST and ADC ratio were 37.9% and 62.1%, respectively. A higher number of prior TACE procedures (p=0.037), female gender (p<0.001) and BCLC C (p=0.03) were associated with worse survival. There was no correlation between disease/treatment characteristics and response according to mRECIST. A higher number of TACE procedures was associated with response according to ADC ratio. Multivariable analysis showed that response based on ADC ratio remained signi cantly related to survival (p=0.041). Conclusion: Change in ADC-ratio following TARE is an independent predictor for survival in patients who previously underwent TACE for HCC. SS 12.5 Combined diffusion-weighted MRI with conventional T2 and T1 in-phase/out-phase sequences: a short screening protocol for liver metastases S. De Vuysere, R.C. Dresen, V. Vandecaveye; Leuven/BE Purpose: To evaluate whether a short MRI protocol consisting of diffusionweighted imaging (DWI), T1 in-phase/out-of-phase and T2-weighted sequences can accurately detect liver metastases without the need of gadoliniumbased contrast. Material and methods: Liver MRI was performed in 124 consecutive patients with cancer. Two independent readers with different experience level (reader 1: 1 year, reader 2: 9 years) retrospectively reviewed the DWI, T2 and T1 inphase/out-of-phase sequences. Both readers were blinded to gadolinium-enhanced images. Metastases were de ned as lesions with high b1000 signal intensity and intermediate or absent signal intensity on T2. Histopathology or 2-year imaging follow-up was the reference standard. Results: Thirty-eight patients were diagnosed with liver metastases and 86 without. Reader 1 made a de nitive diagnosis in 104/124 (84%) patients, yielding a sensitivity of 97.1%, speci city of 90.0% and NPV of 98.4%. He needed additional post-contrast images to make a de nite diagnosis in 20 patients (16%). Reader 2 made a de nitive diagnosis in 122 of 124 (98%) yielding a sensitivity of 81.1%, speci city of 94.1% and NPV of 92%. He needed additional post-contrast images in only 2 patients (1.6%). Conclusion: DWI, T2 and T1 in-phase/out-of-phase sequences allowed accurate detection of liver metastases in an experienced reader. In the future, this time-ef cient protocol could be used for screening of liver metastases, without the need for post-contrast imaging. Purpose: The purpose of this study was to examine the diagnostic accuracy of CEUS in the diagnosis of focal liver lesions, which were undetermined at the initial CT scan. Material and methods: Patients with CT-undetermined focal liver lesions were included in this study. A total of 78 patients were evaluated. All patients were examined with ultrasound scanners with contrast-speci c software, and SonoVue intravenous bolus. The standard of reference was a composite consisting of percutaneous biopsy, surgical resection, PET/CT and clinical follow-up. Results: The patients had 163 undetermined focal liver lesions, mean size 1.1 cm, range 0.1–5.3 cm. There were 18 malignant and 145 benign liver lesions, as de ned by the standard of reference. In differentiating between benign vs. malign CEUS demonstrated sensitivity, speci city, PPV, NPV and accuracy of 94.4% (95% CI: 56.3% to 99.5%), 99.3% (95% CI: 94.9% to 99.9%), 94.4% (95% CI: 56.3% to 99.5%), 99.3% (95% CI: 94.9% to 99.9%) and 98.7% (95% CI: 94.9% to 99.7%), respectively. If the CEUS-inconclusive results were assumed to indicate malignancy, then sensitivity, speci city, PPV, NPV and accuracy would be 95.8% (95% CI: 66.4% to 99.6%), 98.6% (95% CI: 94.4% to 99.7%), 92.0% (95% CI: 65.1% to 98.6%), 99.3% (95% CI: 95.0% to 99.9%), 98.2% (95% CI: 94.4% to 99.5%). Conclusion: CEUS is useful in differentiating between malignant and benign focal liver lesions in clinical practice. SS 12.7 Gadoxetic acid-enhanced MR imaging reflects coactivation of -catenin and hepatocyte nuclear factor 4 in HCC A. Kitao, O. Matsui, N. Yoneda, K. Kozaka, S. Kobayashi, W. Koda, T. Minami, D. Inoue, T. Ogi, K. Yoshida, T. Gabata; Kanazawa/JP Purpose: To clarify the correlation of the co-activation of -catenin and hepatocyte nuclear factor (HNF) 4 with the  ndings of gadoxetic acid-enhanced MRI, organic anion transporting polypeptide (OATP) 1B3 expression and histological differentiation grade in HCC. Material and methods: Surgically resected 196 HCC in 174 patients were enrolled in this study. HCC were classi ed into four groups by immunohistochemical expression of -catenin, glutamine synthetase (GS) and HNF4 : -catenin/GS(positive: +) HNF4(+), -catenin/GS(+) HNF4(negative: -), -catenin/GS(-) HNF4(+) and -catenin/GS(-) HNF4(-). We compared the four groups regarding enhancement ratio on hepatobiliary phase of gadoxetic acid-enhanced MRI, immunohistochemical OATP1B3 expression and histological differentiation grade. Kruskal–Wallis test and Steel–Dwass multiple comparison test were used for the statistical analyses. Results: Enhancement ratio in HCC with -catenin/GS(+) HNF4(+) was signi cantly higher than those of the other 3 groups (median 2.49, 0.53, 0.66, 0.64, in the above-mentioned order, P<0.001). HCC with -catenin/GS(+) HNF4(+) showed the highest OATP1B3 expression grade (P<0.001) and the highest differentiation grade among the 4 groups (P=0.002). Conclusion: Co-activation of -catenin and HNF4 promotes OATP1B3 expression, and consequently increase enhancement ratio on gadoxetic acidenhanced MRI and differentiation grade in HCC. Using imaging to identify the molecular background of liver lesions (radiogenomics/proteomics) will help future personalized medicine in HCC. SS 12.8 The added value of diffusion-weighted imaging at 3T MRI in differentiating malignant from benign thrombus of the portal vein E. Guler1, E. Ozturk1, M. Yuksel2, T. Kose1, M. Harman1, N.Z. Elmas1; 1Izmir/TR, 2Kahramanmaras/TR Purpose: To determine the utility of diffusion-weighted imaging (DWI) and conventional 3T MRI in differentiating malignant portal vein thrombus (PVT) from benign PVT. Material and methods: A retrospective database search for examinations obtained with 3T MRI including DWI from January 2011 through December 2016 for “PVT” was performed. A thrombus was considered malignant if it enhanced on MRI (≥15% during arterial phase when compared with precontrast images). Twenty-three patients with malignant PVT and 14 patients with benign PVT were identi ed. Two independent reviewers recorded the maximum diameter of portal vein, signal intensity of PVT on T2-weighted images and DWI. The mean apparent diffusion coef cient (ADC) of the malignant and benign PVTs were calculated and compared using Mann–Whitney U test. Comparisons of the signal intensity of the PVTs on T2-weighted images and DWI were evaluated using Pearson Chi-square and Fisher’s exact tests. The interobserver aggreement was assessed using the kappa statistic and intraclass correlation. Results: The mean ADC values of malignant and benign PVTs were 0.95±0.19x10-3mm2/s and 1.87±0.26x10-3mm2/s, respectively, with signi cant difference (p=0.00). There were signi cant differences between two groups for the comparison of signal intensity on T2-weighted images and DWI (p<0.05). The interobserver correlation for ADC values was 0.95, indicating excellent correlation. Conclusion: DWI enables differentiation between malignant and benign PVT. An interesting  nding is that conventional sequences and DWI can predict malignant PVT in the absence of apparent tumor on MRI. SS 12.9 Diagnostic performance of intravoxel incoherent motion and conventional diffusion-weighted imaging in the differential diagnosis of benign and malignant portal thrombosis E. Kaya, B. Koyuncu Sokmen, S. Server, A. Oz, N. Inan, C. Balci, Y. Tokat; Istanbul/TR Purpose: To evaluate the diagnostic accuracy of intravoxel incoherent motion (IVIM) and conventional diffusion-weighted imaging (DWI) parameters in the differential diagnosis of benign and malignant portal vein thromboses (PVT). Material and methods: Twenty-eight patients (18 men,10 women) with PVT (13 benign, 15 malignant) were included in this retrospective study. All patients were examined by 1.5 T MRI with the use of four-channel phased array body coil. In addition to routine pre-and postcontrast sequences, IVIM (16 different b factors of 0-1300s/mm2) and conventional DWI (3 different b factors of 50,400,800s/mm2) were obtained. Two different ADC maps reconstructed from conventional DWI (ADCcon) and IVIM (ADCivim). The mean D (true diffusion coef cent), D* (pseudo-diffusion coef cient associated with blood ®ow) and f (perfusion fraction) values were also calculated from IVIM. Quantitatively, both ADCcon and ADCivim, D, D* and f values were compared between the groups by Student’s t test. To evaluate the diagnostic performance of the parameters, recevier operating characteristic (ROC) analysis was performed. Results: The ADCcon, ADCivim, and D values of the malignant PVT were signi cantly lower than those of benign ones (p=0.011, p=0.008, and p=0.046, respectively). The differences of f and D values were statistically not signi cant. The best discriminative parameter was the ADCivim (mean ADCivim was 1,15 ±0,32x10-3 for benign PVT; 0,86 ±0,26x10-3 for malignant PVT). Conclusion: ADC values measured with DWI and IVIM may help differantiation of benign and malignant PVT. SS 12.10 withdrawn by the authors Conference Suite II MC 3.2 Scienti c Session SS 13 Technical advances in abdominal imaging SS 13.1 Computed tomographic perfusion imaging for the prediction of response and survival to transarterial chemoembolization of HCC P. Popovic, M. Garbajs, A. Leban, K. Kregar, M. Štabuc, R. Dežman, M. Bunc; Ljubljana/SI Purpose: To retrospectively evaluate CT perfusion imaging (CTPI) parameters in predicting the response to treatment and overall survival of HCC treated with drug-eluting beads transarterial chemoembolization (DEBTACE). Material and methods: Between December 2010 and January 2013, eighteen patients (17 men, 1 woman; mean age 69 ± 5.8 years) with intermediate-stage HCC underwent CTPI of the liver prior to DEBTACE. Treatment response was evaluated on follow-up imaging according to mRECIST. Pre-treatment CTPI parameters were compared between responders (complete response) and non-responders (partial response) with a Student t test. For survival analysis patients were divided into two groups on the basis of the threshold value for each parameter. Results: CTPI parameters of both groups did not show statistically signi cant difference. The mean survival time was 25.4 ± 3.2 months (95% CI: 18.7-32.1) with one- and two-year survival 83.3% and 50%, respectively. Survival was statistically signi cantly longer in patients with blood ®ow (BF) lower than 50.44 ml/100ml/min (p = 0.033), blood volume (BV) lower than 13.32 ml/100ml (p = 0.028) and time to peak (TTP) higher than 19.035 s (p = 0.015). Conclusion: CTPI enables prediction of survival in patients with intermediatestage HCC, treated with DEBTACE based on the pre-treatment values of BF, BV and TTP perfusion parameters. CT perfusion imaging cannot be used to predict treatment response to DEBTACE. SS 13.2 High-resolution vascular photoacoustic imaging in healthy volunteers using a Fabry-Perot US sensor A. Plumb, N.T. Huynh, J. Guggenheim, E. Zhang, P. Beard; London/GB Purpose: Many gastrointestinal tract disorders cause abnormal vasculature. We aimed to determine if a new photoacoustic imaging (PAI) system can successfully depict microvascular circulatory changes in response to thermal stimuli. Material and methods: Following ethical permission, 13 consenting subjects underwent PAI of the index  ngertip as proof-of-concept. The images were obtained after immersion in either warm (30-35°C) or cold (10-15°C) water to promote vasodilation or vasoconstriction, respectively. The PAI instrument used a Fabry-Perot interferometer as the ultrasound sensor, a 30Hz 750nm excitation laser and a 1550nm interrogation laser. Images were acquired through a 14x14x14mm volume over 90seconds and reconstructed of®ine for analysis. Volumetric imaging datasets were evaluated subjectively by two independent radiologists, and quantitatively by voxel-counting, to determine if PAI could depict cold-induced vasoconstriction. We also measured the fullwidth at half-maximum (FWHM) of resolvable vessels. Results: Vessels were visible in all participants, with mean FWHM of 125μm. Both radiologists used PAI to correctly identify vasoconstricted  ngertip capillary beds in 100% of cases (95%CI 77.2-100.0%, p<0.001 vs. chance). The number of voxels exhibiting vascular signal was signi cantly smaller after cold vs. warm water immersion (cold: 5263 voxels; warm: 363,470 voxels, p<0.001). Conclusion: PAI achieves rapid, volumetric, high-resolution imaging of microvasculature, and it is responsive to vasomotor changes induced by thermal stimuli. PAI may, therefore, be of value in assessing diseases with abnormal vasculature such as in®ammatory bowel disease (IBD). SS 13.3 Evaluation of different methods to optimize contrast media amount in abdominal CT of obese patient F. Rivosecchi, D. Caruso, M. Rengo, D. Bellini, M. Zerunian, A. Laghi; Latina/IT Purpose: To prospectively compare two different approaches for calculating the lean body weight (LBW) and the amount of intravenous contrast media (CM) for MDCT of the abdomen in obese patients. Material and methods: Nineteen patients with a BMI greater than 35 kg/ m2 were included and underwent MDCT of the abdomen. The amount of CM injected was computed according to the patient’s LBW which was estimated using the Boer formula (Group A) or the James formula (Group B). CNR of liver, kidney, portal vein, aorta and pancreas and patient’s characteristics and CM volume were compared and analyzed. Results: Group A has a superior BMI than Group B (38.56±6.31 vs. 37.23±5.54 kg/m2) while an inferior LBW was observed for Group A vs Group B (59.15±12.23 vs 59.79±12.68 kg).  Group A provides greater CNR (liver 3.64±1.12; kidney 13.53±7.2; portal vein 10.22±6.34; aorta 11.93±3.45, pancreas 2.51±0.98) during the portal venous phase compared to CNR of Group B (liver 3.38±2.11; kidney 9.87±6.55; portal vein 7.70±3.43, aorta 8.07±2.69, pancreas 2.35±1.12). A signi cant difference was observed for CNR of kidney, portal vein and aorta (p<0.05) despite a lower amount of CM was administered in Group A compared to Group B (115.45±13.3 ml vs 116.64±12.56, p>0.05). Conclusion: CM volume using Boer formula signi cantly improves parenchymal enhancement in obese patients despite a lower amount of CM. SS 13.4 CT-liver perfusion post-processing: the effect of portal vein ROI positioning A. Hatzidakis1, K. Perisinakis1, A. Papadakis1, G. Kalarakis1, E. Savva1, M. Rusiniak2, A. Karantanas1; 1Heraklion/GR, 2Warsaw/PL Purpose: To study the effect of portal vein (PV) ROI-positioning during processing of CT-liver perfusion on resulting perfusion maps. Material and methods: Thirty patients with diagnosed HCC-nodules were subjected to CTLP on a modern GE CT-system. Perfusion maps for Mean Slope of Increase (MSI), TTP, BF, and Tmax were generated using CT perfusion 4D processing software, by positioning the reference ROI on extrahepatic (EX) PV. Maps were also generated by positioning the reference-ROI on intrahepatic (INPV), right (RTPV), left-PV (LTPV) and splenic vein (SV). ROIs were appropriately set on HCC nodules and non-tumorous parenchyma. Wilcoxon test was employed to study differences between values obtained for different reference-ROI positioning. ROC-analysis was employed to evaluate differences in HCC discriminating power of perfusion parameters for different ROI-positions. Results: The use of INPV or RTPV instead of EXPV reference-ROI did not signi cantly change perfusion maps for both non-tumorous and HCC areas. The use of LTPV and SV reference-ROI signi cantly changed the BF-map for non-tumorous parenchyma (p<0.05) and Tmax-map for HCC nodules (p<0.05), respectively, leaving all other maps unchanged. Positioning reference-ROI on INPV, RTPV, LTPV or SV instead of the EXPV did not signi cantly change the power of studied perfusion maps to discriminate HCC from non-tumorous parenchyma. Conclusion: In case of partial or total PV thrombosis, where positioning EXPV reference-ROI is not feasible, reliable perfusion-maps may be derived by positioning reference-ROI on INPV or RTPV. SS 13.5 Clinical significance of postinterventional contrast medium injection after CT-guided drainage placement H. Goessmann, M. Haimerl, L. Beyer, W. Uller, V. Teusch, F. Poschenrieder, A.G. Schreyer, L.M. Dendl; Regensburg/DE Purpose: The aim of this study was to evaluate the added clinical value of an additional postinterventional control scan after CT-guided drainage placement with contrast medium (CM) via the newly placed drain. Material and methods: All CT-guided drainages of ®uid collections between January 2014 and September 2016 in a maximal care hospital were included in this study. The patients were divided into 2 subgroups; patients that underwent surgery before developing the ®uid collection and patients that did not. Drainages that were additionally ®ushed with CM were evaluated to assess whether the additional scan was helpful for either detecting the source of the ®uid collection (e.g. anastomosis insuf ciency) or additional cofactors (e.g. intestinal  stulas in pancreatitis) and whether or not this information led to an immediate change of therapy. Results: 499 drainages in 352 patients were detected, 197 thereof were postinterventionally ®ushed with CM. 51 (26%) of those showed a clinically signi cant additional  nding. An immediate change of therapy was found in 19 cases (9%). The group that underwent surgery showed no statistically signi cant difference to the group that did not. Conclusion: An additional scan with CM injection via the newly placed drain revealed clinically signi cant additional information in almost 26% in this study. In 9% of the cases this information led to an immediate change of therapy. SS 13.6 The effect of adaptive statistical iterative reconstruction (ASIR) on CT image heterogeneity analysis in primary colorectal cancer K. Owczarczyk1, D. Prezzi1, M. Siddique1, P. Bassett2, C. Grierson3, D.J. Breen3, G.J. Cook1, V. Goh1; 1London/GB, 2Amersham/GB, 3Southampton/GB Purpose: To determine the effect of adaptive statistical iterative reconstruction (ASIR) on the calculation of image heterogeneity features using contrast-enhanced CTs from patients with colorectal cancer. Material and methods: CTs from 32 prospective patients were reconstructed using 6 different ASIR percentages (0-100%) yielding 6 datasets/case. A single-slice region of interest was drawn around the tumor on the ASIR0% scan and propagated onto remaining datasets. First-order (mean, skewness, kurtosis and entropy), second-order (GLCM: contrast, entropy and homogeneity) and fractal (dimension and lacunarity) features were compared using Bland– Altman statistics, repeat-measure ANOVA (rANOVA) and univariate regression (R2). Results: Mean feature variation (expressed as percentage difference) between ASIR levels ranged from 0.13 to 10.14%; in the majority of cases was <5%. ASIR had no signi cant effect on  rst-order features (rANOVA p values: 0.29, 0.1, 0,2 and 0.6; R2: 0.08, 0.16, 0.11 and 0.03, respectively). Second-order/ fractal features varied signi cantly across ASIR levels (rANOVA p value<0.0001 in all cases) and ASIR had an incremental effect on feature calculation (R2: 0.86, 0.75, 0.57, 0.95 and 0.86). Conclusion: Heterogeneity feature variation was overall modest. While ASIR had little/no effect on  rst-order (non-texture) features, there was a strong correlation between increasing ASIR percentages and higher order features, suggesting that different reconstruction algorithms should not be used interchangeably in image heterogeneity research. SS 13.7 Role of perfusion computed tomography in evaluation and comparison of gastrointestinal stromal tumors (GISTs) and GI lymphomas: a pilot study S. Gupta, J. Kumar, V. Chowdhury; New Delhi/IN Purpose: To assess perfusion characteristics of GIST and GI lymphomas on CT and differentiate and compare CT perfusion parameters with histopathology/immunohistochemistry. Material and methods: 23 adult patients with suspected GIST/GI lymphoma were examined with an initial NCCT of abdomen followed by dynamic CT acquisition of the region of interest using a dedicated perfusion protocol. Postprocessing perfusion maps were created and perfusion parameters: blood ®ow (BF); blood volume (BV); permeability (PMB) and mean transit time (MTT) of both involved and uninvolved parenchyma were recorded for comparison. Only histopathologically/immunohistochemistry con rmed tumors were used in  nal analysis (18/23). Statistical signi cance was calculated using Mann– Whitney U test and p value<0.05 was considered as signi cant. Results: Both GISTs and GI lymphomas; irrespective of the size and location showed signi cantly higher perfusion parameters compared to the baseline (p=0.001). High-grade GISTs (graded histopathologically) showed signi cantly higher BF, PMB & lower MTT (p<0.05) than low-grade GISTs; however, with similar BV. MTT was the only parameter which showed statistical signi cance (p=0.021) in differentiating GISTs & GI lymphomas (reduced more in GI lymphomas; 6.07+/-2.67 vs 11.57+/-4.93s). Mean BF was signi cantly lower in GI lymphomas showing mural thickening >5cm than those showing mural thickening<5cm (75.87+/-31.25 vs 110.24+/-61.54 ml/100ml/min) indicating outgrowth of blood supply by increased mural thickening. Conclusion: Perfusion CT is useful in complementing MDCT in characterizing and differentiating between different grades of these tumors which are close imaging mimics. SS 13.8 Whole-liver perfusion CT with a 160-mm/256-row scanner CT in cirrhotic patients: preliminary experience R. Faletti, M. Fronda, C. Dianzani, M. Gatti, A. Ferraris, F. Marchisio, P. Fonio, G. Gandini; Turin/IT Purpose: To analyse the feasibility and the dosimetric aspects of whole-liver perfusion CT (WLpCT) in cirrhotic patients. Material and methods: Eight cirrhotic patients underwent WLp with a 160-mm/256-row CT scanner (GE Healthcare, Revolution CT). Blood ®ow (BF), time to peak (TTP), blood volume (BV), mean transit time (MTT), hepatic arterial fraction (HAF) and permeability surface area product (PS) were measured by two double-blinded radiologists both in the HCC and in the surrounding parenchyma. The WLp CT dose index (CTDI) and dose-length product (DLP) were compared to those of a standard 4-phase CT performed in a control group of 127 patients. Data were analysed using Wilcoxon signed-rank test. Results: A total of 10 HCC were detected and histologically proven. Five of them appeared hypovascular on a previous examination (3 contrast-enhanced ultrasound and 2 gadoxetic acid-enhanced MRI). HCC had increased HAF and BV when compared with the surrounding parenchyma (respectively, p=0.01 and p=0.02), without signi cant differences in HAF between typical and atypical nodules (p>0.05). The mean DLP of the WLpCT were similar to that of 4-phase CT performed with the same scanner CT (967.5 vs. 1093 mGy-cm; p>0.05). Conclusion: WLpCT is a feasible technique in the evaluation of cirrhotic liver with promising results in the assessment of typical and atypical HCC, without signi cant increase in radiation dose. SS 13.9 Noise-optimized virtual monoenergetic dual-energy CT angiography can improve diagnostic accuracy for the detection of active arterial abdominal bleeding J.L. Wichmann, S.S. Martin, D. Leithner, T.J. Vogl, M.H. Albrecht; Frankfurt am Main/DE Purpose: To evaluate the diagnostic accuracy of noise-optimized virtual monoenergetic imaging (VMI+) regarding the detection of active arterial abdominal bleeding at dual-energy CT angiography (DE-CTA) in comparison with standard image reconstruction. Material and methods: DE-CTA datasets of 71 patients (46 men; 63.6±13.3 years) with suspected arterial bleeding of the abdomen or pelvis were reconstructed with standard linearly blended (F_0.5), VMI+, and traditional monoenergetic (VMI) algorithms in 10-keV increments from 40 to 100 keV. Attenuation measurements were performed in the descending aorta, area of hemorrhage, and the feeding artery to calculate contrast-to-noise ratios (CNR) in patients with active arterial bleeding. Based on quantitative image quality results, the best series for each reconstruction technique were chosen to separately analyze the diagnostic performance of three blinded radiologists for the detection of active arterial bleeding. Results: Thirty-six patients showed  ndings of acute arterial bleeding. Mean CNR was superior in 40-keV VMI+ compared to all VMI series (all P<0.001), which showed highest CNR at 70 keV, as well as standard F_0.5 images (21.6±7.9, 12.9±4.7, and 10.4±3.6, respectively). Area-under-the-curve analysis for detection of arterial bleeding showed signi cantly superior (P<0.001) results for 40-keV VMI+ (0.963) compared to 70-keV VMI (0.775) and F 0.5 image series (0.817). Conclusion: Diagnostic accuracy for the detection of active arterial bleeding in the abdomen can be signi cantly improved using noise-optimized VMI+ reconstructions at 40 keV compared with standard linearly blended and traditional VMI series in DE-CTA. SS 13.10 withdrawn by the authors Conference Suite II MC 2 Scienti c Session SS 14 Biliary tree and gallbladder new imaging and treatment considerations SS 14.1 Utility of CT texture analysis in assessing for oncogene FGFR2 fusion in cholangiocarcinoma: a radiogenomic pilot study S. Holemon1, A. Silva1, C. Zwart1, G. Yang1, N. Gaw2, J. Li2, T. Wu2, A. Silva2, T. Deleon1, M. Borad1; 1Scottsdale, PA/US, 2Tempe, AZ/US Purpose: To evaluate multi-parametric modeling on imaging textures from contrast-enhanced CT for identi cation of a therapeutically relevant genomic FGFR2 gene fusion in advanced cholangiocarcinoma. Material and methods: A retrospective study of 33 patients with intrahepatic cholangiocarcinoma who had whole-genome and whole-transcriptome tumor analyses as well as contrast-enhanced CT was performed. Of the 33, 15 were positive for FGFR2 gene fusion. Matched-size regions of interest (ROIs) over areas of non-necrotic tumor and unaffected liver during the portal venous phase were drawn. The paired ROIs for each patient were then processed via an imaging analytic pipeline for (1) ROI normalization, (2) texture panel creation, and (3) machine learning predictive model development. Results: Using the developed model, accurate FGFR2 fusion classi cation was achieved in 90.91% of cases (sensitivity = 86.67%, speci city = 94.44%). Conclusion: Utilizing advanced analytics, multi-textural data obtained from CT images have the capability to detect genetic aberrations in intrahepatic cholangiocarcinoma, including FGFR2 gene fusion. This is particularly compelling in light of improved treatment options for patients with FGFR2 gene fusions through the use of FDA-approved kinase inhibitors with pan-FGFR activity and/or FGFR2 inhibitory activity. If imaging could be used to identify patients with an increased likelihood of FGFR2 gene fusion, targeted chemotherapy treatment could be more rapidly deployed with the potential to eliminate the need for invasive core biopsies as well as the expense and turnaround time of genomic analysis. SS 14.2 Biliary leak after percutaneous biliary stenting: prevention with biopsy sealing device T. Biondi, D. Bellini, D. Caruso, M. Rengo, M. Zerunian, A. Saltarelli, A. Laghi; Latina/IT Purpose: To prospectively evaluate the effectiveness of biliary sealing with a compressed collagen foam plug in preventing the development of complication related to biliary leak following biliary stenting. Material and methods: This single-center, HIPAA-compliant prospective study was approved by our Institutional Review Board. Forty patients with malignant biliary obstruction (16 men, 24 women), with clinical indication for biliary stenting, were randomly assigned in a 1:1 ratio, to receive the biliary sealing device or not. All patients were masked to treatment allocation. The primary endpoint was the prevalence of complications related to perihepatic biliary leak after procedure; hospital stay was also evaluated after procedure and abdominal pain was perceived using a 10-point scale. Results: The prevalence of postprocedural biliary leak was 83% (15 of 18 patients) in the control group and 5% (1 of 18 patients) in the plug group. None of patients in both groups required abdominal drainage. Hospital stay was longer for the control group compared to plug group (30% increase in hospital stay) and the scores of abdominal pain perceived after procedure were signi cantly higher for the control group (5 ± 2 vs 3± 2; P value 0.032). Conclusion: Although further experience is necessary, transhepatic collagen foam plug placement might be a simple and effective supplement for avoiding biliary leak after percutaneous biliary stenting. SS 14.3 Effect of hepatobiliary MR contrast agent injection on signal intensity of peritoneal and pleural fluid effusions M. Ciolina1, M. Di Martino1, O. Bruno2, R. Pommier2, V. Vilgrain2, M. Ronot2; 1Rome/IT, 2Clichy/FR Purpose: To describe the effect of hepatobiliary MR contrast agents (HBCA) injection on signal intensity of peritoneal and pleural ®uid effusions on T1weighted MR sequences. Material and methods: From October 2015 to May 2016, consecutive patients with peritoneal/pleural effusions, explored by HBCA-MRI (Gd-BOPTA or Gd-EOB-DTPA) at 1.5T and 3T were retrospectively included from two centers. Signal intensity of ®uids were classi ed as hypo/iso/hyperintense compared to the splenic parenchyma, before and after injection. The relative signal enhancement (RE) and the signal to noise ratio (SNR) on the pre- and contrastenhanced sequences were calculated. Results: 139 patients with peritoneal/pleural effusions without biliary/vascular leakage (mean 60±10-yo, 96 males, 69%) were included. MR was performed for chronic liver disease (n=105), cancer staging (n=21), and others (n=15). On hepatobiliary phase (HBP) after Gd-BOPTA, peritoneal ®uid appeared hyper/ isointense in 88-100%, and pleural effusion in 100% of the patients. On HBP after Gd-EOB-DTPA, all effusions remained hypointense. Signal intensity increased with both HBCA over time but RE was signi cantly higher after GdBOPTA (p=0.002 and <0.001 for peritoneal and pleural ®uid). After Gd-BOPTA, it was signi cantly higher in patients with chronic liver disease (p=0.009). Conclusion: Signal intensity of pleural and peritoneal ®uid progressively increases after HBCA in the absence of vascular of biliary leakage, regardless of the  eld strengh. As most patients explored with Gd-BOPTA had hyperintense ®uid effusions during HBP, we do not recommend this contrast agent for diagnosing biliary leak. SS 14.4 Imaging findings in gangrenous cholecystitis retrospective analysis of histopathologically proven cases: largest Indian tertiary care experience B. Sureka, A. Rastogi, A. Mukund, S.T. Laroia, T.K. Chattopadhyay; New Delhi/IN Purpose: To identify the radiological signs/markers in histopathologically proven cases of gangrenous cholecystitis. Material and methods: A total of 31 patients were evaluated. A retrospective study was done wherein imaging (USG, CT or MRI) data of patients and cases operated at our institute with histopathological evidence of gangrenous cholecystitis were analyzed. For this, the histopathology records of operated cases of acute cholecystitis between January 2012 and August 2016 were searched and cases in which pathology reports mentioned necrosis, transmural in®ammation with transmural ulceration were included in the present study. Results: 31 patients (male 13; female 18; mean age 49.2 years, age range 24–74 years) were included in the study. The mean wall thickening of the gallbladder wall was 6 ± 1.93 mm. Gallstones were present in 30 cases. Mural edema, mural striation, pericholecystic ®uid and intraluminal membranes were seen in 27, 18, 20 and 14 cases, respectively. Pericholecystic stranding was seen in 24, gas in 3. Intraluminal membranes were present in 14 cases with mean short-axis distension of 4.6 cm and absent in 17 cases with mean shortaxis distension of 3.94 cm (p=.041). 11/14 (78.6%) had mural striation (p=.036). All cases with gallbladder wall hemorrhage had intraluminal membranes. Focal decreased wall enhancement was seen in 9/10. Conclusion: Imaging signs and markers like gallbladder distension (≥ 4cm), membranes, mural striation and abnormal wall enhancement suggest high probability of gangrenous change in acute cholecystitis. SS 14.5 IgG4-associated cholangitis: radiological features C. Valls, L. Louizou, N. Voulgarakis, A. Grigoriadis, N. Luotsinen, E. Axelsson, N. Kartalis; Stockholm/SE Purpose: IgG4-associated cholangitis (IAC) is a systemic in®ammatory disease in the biliary tree with a lymphoplasmacytic in ltrate of IgG4-positive cells and biliary strictures. The purpose of our study was to describe the imaging  ndings of IAC and to determine retrospectively the diagnostic performance MR and CT in diagnosis of this rare entity. Material and methods: We reviewed our pathological and surgical databases from 2005 till 2014. Under this period 329 patients were operated because of suspected hepatobiliary malignancy and had been examined with CT and MR. Among these patients we identi ed 5 patients who turned out to have IAC at histology. In addition we identi ed 9 patients with histopathology-proven autoimmune pancreatitis (AIP) which showed biliary strictures. We reviewed retrospectively clinical, serologic, and imaging characteristics of all patients. Results: There were 10 men and 4 women with a mean age of 68 y. In 66% of the cases clinical presentation was obstructive jaundice. Biliary strictures had a median length of 4.5 cm. Median width of biliary periductal thickening was 4 mm. IgG4 levels were increased in 66% of the cases. Only 40% of the cases were preoperatively diagnosed with IAC . No patient with isolated IAC was diagnosed preoperatively. Conclusion: Preoperative radiological diagnosis of IAC remains elusive if not associated to AIP or positive serology. SS 14.6 CT characteristics of periaortitic/periarteric lesions associated with IgG4-related disease Y. Fujinaga, M. Kitano, A. Yamada, M. Kurozumi, S. Kawakami, H. Hamano, S. Kawa, M. Kadoya; Matsumoto/JP Purpose: To evaluate CT characteristics of peroaortic/arteric lesions associated with IgG4-related disease. Material and methods: We reviewed the database of our hospital and 193 patients (141 male and 52 female), who were diagnosed with IgG4-related disease based on the comprehensive or each organ’s diagnostic criteria of IgG4related disease between 2003 and 2015, and underwent chest-pelvic CT before steroid therapy, were enrolled in this study. We investigated the CT  ndings, frequency and the location of periaortic/arteric lesions. Results: Wall thickening (i.e., circumferentially involved soft tissue density on the adventitial side of aorta/artery) was observed in 66 (34.2%) of 193 patients. The median maximum wall thickening of the abdominal aorta was 3 mm (range, 1–15 mm). All of the lesions were homogeneously enhanced at the delayed phase of contrast-enhanced CT. The locations of the lesions were abdominal aorta at the inferior mesenteric artery (IMA) bifurcation in 57 (86.4%) patients, common iliac artery (CIA) in 31, thoracic aorta in 7, IMA in 4, splenic artery in 3, subclavian artery in 2, coronary artery, brachiocephalic artery and external iliac artery in 1. Periaortic lesions were extended to the CIA in 27 patients. Multiple lesions were seen in 14 patients. Follow-up CT was available in 33 patients and all of the lesions were improved after steroid therapy. Conclusion: Periaortic/arteric lesions associated with IgG4-related disease were occasionally seen as aortic wall thickening commonly at the IMA bifurcation. SS 14.8 Frequency of bile duct confluence variations in subjects with pancreas divisum A. Gursoy Coruh, B. Gulpinar, H. Bas, A. Erden, I. Erden; Ankara/TR Purpose: The aim of this study was to evaluate the frequency of branching pattern variations of the bile ducts at the hepatic con®uence in patients with pancreas divisum (PD). Material and methods: A search was performed through the PACS system using keyword “pancreas divisum” to identify patients. MRCP images of 89 patients who were diagnosed with PD between March 2013 and November 2016 were retrospectively analyzed for the presence of bile duct variations. Matched controls were 89 consecutive patients without PD investigated during the same period. Variations of the biliary tract were grouped into 7 types according to McSweeney et al.’s classi cation. Results: Biliary tract variations were detected in 68 of 178 patients. Branching pattern of bile duct con®uence could be evaluated in 79 MRCPs with PD. The typical branching pattern was detected in 51 of the PD patients (57.3%) and 59 of (66.3%) controls. Subjects with PD were not more likely to have biliary tract variation (p= 0.217) compared with the control group. The most common variation in subjects with PD was type 3 variation (43.6%). Conclusion: Nearly in half of the patients with PD and one third of patients without PD, MRCPs showed atypical bile duct con®uence pattern. The most common variant was right posterior duct draining into the left hepatic duct. SS 14.9 Gallbladder 3D volumetric analysis scan: a new alternative to HIDA scan for functional gallbladder disorder M.A. Ghouri, K. Bonam, B. Stenberg, T. Ali, A. Ncneill; Newcastle upon Tyne/GB Purpose: Functional gallbladder disorder (FGD) is de ned as biliary pain resulting from a primary gallbladder motility disturbance in the absence of de nite gallbladder pathology. The diagnosis is considered in patients with biliarytype-pain with no de nite potential cause identi ed. The aim of study was to determine whether gallbladder-ejection-fraction (EF) calculated with 3D-Gallbladder –volumetric-analysis-scan (USS-GB-VA) correlates with EF calculated with HIDAscan. Material and methods: Patients were included based on the diagnostic criteria from the Rome III Guidelines for FGD. Retrospective data was collected from PACS for patients who underwent USS-GB-VA and/or HIDA scan for period between Sep2014–Aug2016. USS-GB-VA was performed using Philips Epiq;X6-1-volume-acquisition-with-stacked-ellipses after pre and post fatty meal(FM) consisting of Mars-bar® and milky-coffee. All measurements (fasting, 20-mins and 40-mins postFM) were made with error-margin of +/-11%. A baseline EF of ≥35% at 20 min was considered to be normal. Results: A total of 66 patients were analysed (M:23-F:43, with an average age of 45.6 to 48.6 for M and F, respectively), of which 44 patients had USS-GBVA, 24 patients had HIDA and 13 patients both. Of these 13 patients, 6 patients (6/13-46%) had matching USS-GB-VA and HIDA results, 1 patient, who had an abnormal EF-on USS-GB-VA, had a normal subsequent HIDA scan and 1patient who had normal- USS-GB-VA had abnormal subsequent-HIDA-scan. Of these 13-patients, only 4-patients underwent cholecystectomy and rest were treated conservatively. Conclusion: USS-GB-VA can be potentially used as  rst line diagnostic test for FGD with HIDA-scan to be used safely as an alternative investigation-ofchoice. SS 14.10 Contrast-enhanced computer tomography evaluation of ERCP complications R. Cannella, D. Picone, D. Giambelluca, G. Caruana, A. Calandra, I. Cannella, T.V. Bartolotta, M. Midiri, G. Lo Re; Palermo/IT Purpose: The aim of the study was to analyze the diagnostic role of contrast agent administration in CT in emergency patients with suspected complication after ERCP. Material and methods: From January 2013 till December 2016, ninety-six patients (46 males and 39 females, mean age 66.7 years), who recently underwent ERCP, arrived at emergency department of radiology with clinically suspected complication. All patients were studied with CT. The results were statistically analyzed. Results: In sixty-one patients the CT exam was performed with contrast agent administration, thirty- ve had only the baseline CT. The diagnostic accuracy of contrast-enhanced CT was signi cantly higher than baseline CT (93% vs 73%, P <0.05). Fifty-four patients had normal CT scans except for the presence of ordinary post-procedural  ndings such as air and contrast agent in the biliary tree and gallbladder. The presence of complications was found in 42 cases (43.8%). The most common  nding was perforation (16.6% of complications), followed by acute pancreatitis (14 cases, 14.5%), infection (8.3%) and gastroduodenal acute bleeding (3.1%). Finally, there was one case of stent misplacement. Conclusion: Although ERCP has a low incidence of adverse events (5% of cases described in the literature), contrast-enhanced CT is the technique of choice for emergency imaging when they are suspected. It allows evaluation of the type and severity of complication, and it is a necessary exam for surgical management and treatment. Quelever R.: SS 8.1 Querques G.: SS 8.10 Qureshi A.: SS 3.4 Lombardo F. : SS 7.3 Lonjon J.: SS 12.2 Lo Re G.: SS 11.7, SS 14.10 Louizou L.: SS 14 .5 Lubner M. : SS 5.3 Luciani A.: SS 5 .5, SS 8.1 Luotsinen N. : SS 14.5 Lyn H.: SS 7.1 Lythgoe M. : SS 4.9 Pacciardi F.: SS 1.2, SS 2.1 Paiva F.F.: SS 4.6 Panagiotidou D. : SS 6.7 Papadakis A. : SS 8.2, SS 13.4 Papaderakis G.: SS 6.7 Papanikolaou N. : SS 11.8 Paperlein C.: SS 11.6 Parente D.B. : SS 4.6 Park D.H. : SS 4.2 Park M.-S.: SS 2.2 Pellegrino S. : SS 11.7 Pendse D. : SS 6.7 Perez R.M. : SS 4.6 Perisinakis K. : SS 8.2, SS 13 .4 Perkuhn M. : SS 3.3 Peters N. : SS 3.8 Petmezaris I. : SS 6.7 Petrillo A. : SS 10.1 Petrillo M. : SS 10.1 Picchia S. : SS 3.2 Pickhardt P. : SS 5.3 Picone D. : SS 11.7, SS 14.10 Pigneur F. : SS 5.5, SS 8.1 Plumb A.: SS 10 .4, SS 13 .2 Pommier R .: SS 14.3 Ponsioen C.Y. : SS 6.2, SS 6.7 Popovic P. : SS 13.1 Poschenrieder F. : SS 13.5 Pozzi Mucelli R.: SS 7 .3, SS 7.6, SS 7.10, SS 11 .5, SS 11.10 Pregler B. : SS 9.7 Prezzi D. : SS 3.4, SS 13.6 Prior J.: SS 10.3 Puylaert C . A.J.: SS 6.2, SS 6.7


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ESGAR 2017 Book of Abstracts, Insights into Imaging, 2017, 585-629, DOI: 10.1007/s13244-017-0557-2