Body composition determinants of radiation dose during abdominopelvic CT

Insights into Imaging, Oct 2017

Objectives We designed a prospective study to investigate the in-vivo relationship between abdominal body composition and radiation exposure to determine the strongest body composition predictor of dose length product (DLP) at CT. Methods Following institutional review board approval, quantitative analysis was performed prospectively on 239 consecutive patients who underwent abdominopelvic CT. DLP, BMI, volumes of abdominal adipose tissue, muscle, bone and solid organs were recorded. Results All measured body composition parameters correlated positively with DLP. Linear regression (R2 = 0.77) revealed that total adipose volume was the strongest predictor of radiation exposure [B (95% CI) = 0.027(0.024–0.030), t=23.068, p < 0.001]. Stepwise linear regression using DLP as the dependent and BMI and total adipose tissue as independent variables demonstrated that total adipose tissue is more predictive of DLP than BMI [B (95% CI) = 16.045 (11.337-20.752), t=6.681, p < 0.001]. Conclusions The volume of adipose tissue was the strongest predictor of radiation exposure in our cohort. Main message • Individual body composition variables correlate with DLP at abdominopelvic CT. • Total abdominal adipose tissue is the strongest predictor of radiation exposure. • Muscle volume is also a significant but weaker predictor of DLP.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://link.springer.com/content/pdf/10.1007%2Fs13244-017-0577-y.pdf

Body composition determinants of radiation dose during abdominopelvic CT

Body composition determinants of radiation dose during abdominopelvic CT Patrick D. McLaughlin 0 1 3 5 6 Liam Chawke 0 1 3 5 6 Maria Twomey 0 1 3 5 6 Kevin P. Murphy 0 1 3 5 6 Siobhán B. O'Neill 0 1 3 5 6 Sebastian R. McWilliams 0 1 3 5 6 Karl James 0 1 3 5 6 Richard G. Kavanagh 0 1 3 5 6 Charles Sullivan 0 1 3 5 6 Faimee E. Chan 0 1 3 5 6 Niamh Moore 0 1 3 5 6 Owen J. O'Connor 0 1 3 5 6 Joseph A. Eustace 0 1 3 5 6 Michael M. Maher 0 1 3 5 6 0 Department of Radiology, Cork University Hospital , Wilton, Cork , Ireland 1 Department of Radiology, University College Cork , Cork , Ireland 2 3350-950 West 10th Ave , Vancouver, BC V5Z 1M9 , Canada 3 Department of Emergency and Trauma Radiology, Vancouver General Hospital , Jim Pattison Pavilion North 4 Richard G. Kavanagh 5 Health Research Board Clinical Research Facility, University College Cork , Cork , Ireland 6 Department of Nephrology, Cork University Hospital , Cork , Ireland Objectives We designed a prospective study to investigate the in-vivo relationship between abdominal body composition and radiation exposure to determine the strongest body composition predictor of dose length product (DLP) at CT. Methods Following institutional review board approval, quantitative analysis was performed prospectively on 239 consecutive patients who underwent abdominopelvic CT. DLP, BMI, volumes of abdominal adipose tissue, muscle, bone and solid organs were recorded. Results All measured body composition parameters correlated positively with DLP. Linear regression (R2 = 0.77) revealed that total adipose volume was the strongest predictor of radiation exposure [B (95% CI) = 0.027(0.024-0.030), t=23.068, p < 0.001]. Stepwise linear regression using DLP as the dependent and BMI and total adipose tissue as independent variables demonstrated that total adipose tissue is more predictive of DLP than BMI [B (95% CI) = 16.045 (11.33720.752), t=6.681, p < 0.001]. Conclusions The volume of adipose tissue was the strongest predictor of radiation exposure in our cohort. Tomography; X-ray computed; Radiation dosage; Intra-abdominal fat; Muscle; Skeletal; Body mass index Introduction At present there is a considerable research and industry drive to reduce the radiation dose during CT scanning while preserving image quality and diagnostic accuracy. To date, CT dose reduction technology including automated tube current modulation and iterative reconstruction have facilitated reductions in CT dose to levels approximately 70–75% less than what they were a decade ago. Larger reductions in dose are conceivable with continued research and development and more recent advances in CT technology have facilitated significant dose reductions without sacrificing image quality [ 1–3 ]. Differences in patient size and body weight challenge the pathways of CT dose reduction. It is well recognised that patients with a larger body habitus are exposed to significantly larger doses of ionising radiation during abdominopelvic CT when automated tube current modulation (ATCM) is employed [ 4–7 ]. Previous studies have examined the influence of variables such as body weight [6], body mass index [ 4 ], patient cross-sectional area [ 5, 7 ] and patient AP diameter [8] on imparted dose during abdominopelvic CT with ATCM. However, the abdominal compartment houses many structures of varying volume and density, which impact these indices. These constituents include the solid abdominal organs, soft tissue structures such as abdominal musculature and adipose tissue and bony structures such as the lumbar spine and pelvis. These structures all contribute to patient body weight, body mass index and cross-sectional area and are therefore also likely to contribute individually to the imparted dose during abdominopelvic CT. Although one previous study found an association between subjectively graded quantities of abdominal fat and effective dose [ 9 ], we found no study that has investigated the in-vivo relationship between multiple abdominal body composition variables and radiation dose during CT with ATCM. The authors believe that further investigation of such factors, which may significantly differ among individuals of similar weight, cross-sectional area and BMI [ 10 ], may guide future methods of dose optimisation in abdominopelvic CT and may allow radiologists to refine examination technique and ATCM protocol particularly in obese patients. We therefore designed a prospective, cross-sectional study with the following aims: (1) To identify the body composition determinants of an elevated dose length product during abdominopelvic CT. (2) To determine which of the following parameters is the strongest predictor of radiation dose at CT: & & & & Total abdominopelvic adipose tissue volume Abdominopelvic muscle volume Abdominopelvic bone volume Solid organ volumes Materials and methods Following institutional review board approval, 239 consecutive patients who were referred for clinically indicated a (...truncated)


This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2Fs13244-017-0577-y.pdf

Patrick D. McLaughlin, Liam Chawke, Maria Twomey, Kevin P. Murphy, Siobhán B. O’Neill, Sebastian R. McWilliams, Karl James, Richard G. Kavanagh, Charles Sullivan, Faimee E. Chan, Niamh Moore, Owen J. O’Connor, Joseph A. Eustace, Michael M. Maher. Body composition determinants of radiation dose during abdominopelvic CT, Insights into Imaging, 2017, pp. 1-8, DOI: 10.1007/s13244-017-0577-y