Optimization of Contrast Material Dose for Abdominal Multi-Detector Row CT: Predicting Patient Lean Body Weight by Using Preliminary Transverse CT Images

Abstract

Estimated LBW could be used to determine the contrast material dose and rate during MDCT. The aim of this study is to test the accuracy of a technique for estimation of lean body weight (LBW) from a single multi-detector row computed tomographic (MDCT) abdominal image, using a bioelectrical body composition analyzer scale as the reference standard. CT images of 21 patients with previously measured LBW (mLBW) were processed using computer-assisted, vendor-specific software (Advantage Windows 4.2; GE Healthcare, Inc). For each transverse image, a fat-fraction was automatically measured as the number of fat pixels (−200 to −50 HU) divided by the total number of pixels having an attenuation value ≥−200 HU. Estimated LBW (eLBW) of five single contiguous sections was calculated in each of three abdominal regions (upper abdomen, mid abdomen and pelvis) by multiplying TBW by (1 -fat-fraction). Bland-Altman plot with limits of agreement was used to assess agreement between mLBW and eLBW. The mean mLBW for all patients was 56 kg (range, 39 -75 kg). Mean differences and limits of agreement between mLBW and eLBW measurements for the upper abdomen, mid abdomen and pelvis reported were −8.9 kg (−25.6 kg, +7.5 kg), −10.6 kg (−27.7 kg, +6.4 kg), and +0.5 kg (−12.8 kg, +13.8 kg) respectively. eLBW deriving directly from a transverse CT image of the pelvis can accurately predict mLBW. KeywordsLean Body Weight; Multi-Detector CT; Contrast Dose A. Guerrisi et al. 2

Optimizing Contrast Medium Injection for Coronary CT Angiography Using Myocardial CT Perfusion Data

“…Even when the contrast medium is tailored to body weight, interpatient variability in coronary enhancement can still remain. Previous studies have attempted to tailor the contrast medium dose using other parameters, such as lean body weight [6], body surface area [7], and cardiac output [8,9].…”