Impact of DWI and ADC values in Ovarian-Adnexal Reporting and Data System (O-RADS) MRI score

La radiologia medica https://doi.org/10.1007/s11547-023-01628-3 MAGNETIC RESONANCE IMAGING Impact of DWI and ADC values in Ovarian‑Adnexal Reporting and Data System (O‑RADS) MRI score Lucia Manganaro1 · Sandra Ciulla1 · Veronica Celli1 · Giada Ercolani1 · Roberta Ninkova1 · Valentina Miceli1 · Andrea Cozzi2 · Stefania Maria Rizzo3,4 · Isabelle Thomassin‑Naggara5 · Carlo Catalano1 Received: 24 October 2022 / Accepted: 27 March 2023 © The Author(s) 2023 Abstract Purpose Introduce DWI and quantitative ADC evaluation in O-RADS MRI system and observe how diagnostic performance changes. Assess its validity and reproducibility between readers with different experience in female pelvic imaging. Finally, evaluate any correlation between ADC value and histotype in malignant lesions. Materials and Methods In total, 173 patients with 213 indeterminate adnexal masses (AMs) on ultrasound were subjected to MRI examination, from which 140 patients with 172 AMs were included in the final analysis. Standardised MRI sequences were used, including DWI and DCE sequences. Two readers, blinded to histopathological data, retrospectively classified AMs according to the O-RADS MRI scoring system. A quantitative analysis method was applied by placing a ROI on the ADC maps obtained from single-exponential DWI sequences. AMs considered benign (O-RADS MRI score 2) were excluded from the ADC analysis. Results Excellent inter-reader agreement was found in the classification of lesions according to the O-RADS MRI score (K = 0.936; 95% CI). Two ROC curves were created to determine the optimal cut-off value for the ADC variable between O-RADS MRI categories 3–4 and 4–5, respectively, 1.411 × 10–3 mm2/sec and 0.849 × 10–3 mm2/sec. Based on these ADC values, 3/45 and 22/62 AMs were upgraded, respectively, to score 4 and 5, while 4/62 AMs were downgraded to score 3. ADC values correlated significantly with the ovarian carcinoma histotype (p value < 0.001). Conclusion Our study demonstrates the prognostic potential of DWI and ADC values in the O-RADS MRI classification for better radiological standardisation and characterisation of AMs. Keywords O-RADS · Magnetic resonance imaging · Ovarian carcinoma · Diffusion-weighted imaging (DWI) Introduction Background Ovarian carcinoma is the second most frequent gynaecological cancer in Western countries and is the first cause of death due to malignant neoplasia of the female genital tract [1]. Ultrasonography (US) is considered the first-line imaging approach for the evaluation of adnexal masses (AMs); however, between 18 and 31% of AMs remain indeterminate Lucia Manganaro and Sandra Ciulla have contributed equally to this study and should be considered as co-first authors. * Lucia Manganaro Extended author information available on the last page of the article after ultrasound using the International Ovarian Tumour Analysis (IOTA) simple rules or other ultrasound scoring systems [2–4]. MRI (magnetic resonance imaging) plays a key role as a second-level method in the evaluation of indeterminate adnexal masses detected on US. Recently, the American College of Radiology (ACR) Ovarian-Adnexal Reporting and Data System (O-RADS) MRI committee published a lexicon and risk stratification system for adnexal lesions [5, 6]. O-RADS-MRI allows stratification of the risk of malignancy of adnexal masses based on lesion composition, signal intensity characteristics and solid tissue enhancement pattern. O-RADS MRI system is based on morphological highresolution T1 and T2 WI, dynamic contrast-enhanced (DCE) MRI series (temporal resolution ≤ 15 s) [7, 8] and time–intensity curve (TIC) [9]. TIC is obtained from the DCE-MRI series by placing two circular ROIs within the 13 Vol.:(0123456789) La radiologia medica solid tissue in the adnexal lesion and at the level of outer myometrium and then processed by the perfusion analysis software to determine whether a low-risk, intermediate-risk or high-risk curve is present. The main limitation remains related to the unfeasibility to obtain the enhancement curve, especially when a proper DCE MRI protocol is not performed, not allowing the correct classification into categories 3, 4 and 5. Additionally, TIC for intermediate and high risk cannot be evaluated in patients submitted to hysterectomy [9]. As well demonstrated, limitations in the applicability of TIC are also showed in breast imaging reporting data system (BI-RADS) MRI—due to the great heterogeneity of breast tumours and in nonmass tumours. Actually, a recent study showed that the type II curve (intermediate risk of malignancy) was present not only in malignant lesions (50%) but also in 29.3% of benign lesions [10]. The overlap of TIC patterns between benign and malignant diseases in clinical settings may occur, resulting in inaccurate diagnosis [11]. The primary objective of this study is to systematically introduce DWI and quantitative ADC evaluation in ORADS MRI and observe how diagnostic performance changes. The secondary objective is to evaluate the validity and reproducibility of the O-RADS MRI scoring system among readers with different experience in female pelvic imaging. Finally, the last objective is to assess whether there is a correlation between ADC value and histotype in lesions classified as malignant is reliable. Patient enrolment, data collection and lesion classification according to ORADS-MRI score were retrospective. Magnetic resonance imaging Materials and methods All MRI examinations were performed on a 3-T system (GE Discovery MR 750, GE Healthcare, Milwaukee, WI, USA) and on a 1.5-T system (MAGNETOM Avanto; Siemens Healthcare, Erlangen, Germany) using a 32-channel phasedarray coil positioned on the lower abdomen. Before the beginning of the examination, 20 mg of joscine N-butylbromide (Buscopan; Boehringer Ingelheim, Ingelheim, Germany) was injected intravenously to reduce motion artefacts caused by bowel peristalsis, if not contraindicated. The standard MRI protocol included the following sequences, focusing on the lower abdomen from the pubic symphysis to the iliac crests: T2 fast spin-echo (FSE) weighted imaging (WI). On the sagittal, axial and coronal planes; axial T1 FSE WI with and without fat saturation (LAVA-Flex implementation of Dixon method), axial diffusion weighted images (DWI) with b-values of 0–1000 s/ mm2 to obtain apparent diffusion coefficient (ADC) maps; dynamic T1weighted 3D gradient-echo with fat saturation in the axial plane during contrast uptake and delayed postcontrast T1-weighted 3D gradient echo with fat saturation in the axial plane. Gadolinium chelate (gadoteric acid) was given at a dose of 0.2 mL per kilogram of body weight by using a power injector at a rate of 2 mL/sec, followed by 20 mL of normal saline to flush the tubing. Images were obtained sequentially at 2.4-s intervals beginning 10 s before the bolus injection, for a total of 320 s, Table 1. Patients and study setting Image analysis The study was approve (...truncated)