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Objectives The aim of this study was to perform intermethod comparisons between the following three measures of muscle mass depletion in patients eligible for liver transplantation: 1) fat-free mass index (FFMI) measured by dual-energy x-ray absorptiometry (DXA), 2) appendicular skeletal muscle mass index (ASMI) measured by DXA, and 3) skeletal muscle index (SMI) measured at the third lumbar level by computed tomography (CT). Methods The medical records of patients who received liver transplants between 2009 and 2012 at Karolinska University Hospital were retrospectively reviewed. Adult patients with a chronic liver disease who had both DXA and CT scans performed within a 30-d period during their pretransplant workup were included. Results Appendicular skeletal muscle mass index measured by DXA (ASMIDXA) and skeletal mass index measured by computed tomography (SMICT) provide similar results when assessing the presence of muscle mass depletion in patients with chronic liver diseases and FFMIDXA can be falsely high in patients with ascites. Both ASMIDXA and SMICT thus appear to be useful methods in the pretransplant evaluation of muscle mass depletion both for patients with and without ascites. Conclusions ASMI measured with DXA is a useful alternative method to SMI measured with CT when a CT scan is not clinically indicated or available.

Although computed tomography (CT) is frequently used to determine body composition, the effects of using different CT protocols is not well known. The aim of this study was to determine whether contrast media phase, radiation dose, and slice thickness in CT affect body composition segmentation.Clinically indicated perfusion CTs of the upper abdomen in 20 patients (seven women) between 40 and 87 y of age with high suspicion of hepatocellular carcinoma were analyzed retrospectively. Axial images from the L3 level with varying imaging delay were reconstructed after contrast media injection (18 images per patient), slice thickness (5 images, 2-10 mm), and radiation dose (4 images with one-third to four-thirds of standard dose). Muscle and fat areas were segmented semiautomatically by drawing regions of interests and using established cutoff thresholds. Skeletal muscle index (SMI), steatotic muscle area, and adipose tissue index, as well as muscle attenuation and fat attenuation, were evaluated.Average SMI increased by up to 2.8% after contrast media injection. Steatotic muscle area decreased by ≤13.8%, and adipose tissue index decreased by ≤6.5%. Muscle attenuation increased after contrast media injection, whereas fat attenuation decreased (all P0.001). SMI decreased by 1.9% on average when increasing slice thickness from 2 to 10 mm. Steatotic muscle area increased by ≤3.3%, and adipose tissue index increased by ≤1.5% (all P0.05). Muscle attenuation did not change significantly with reconstruction thickness. Radiation dose had no effect on estimated area of spinal muscle, fatty spinal muscle, or visceral fat.Contrast media have a strong effect on the evaluation of body composition, whereas the influence of slice thickness is less pronounced. Radiation dose can be reduced by ≥66% without significantly affecting segmentation.

Objectives Our purpose was to investigate whether tube potential in contrast-enhanced computed tomography (CT) affects body composition analysis. Methods Images from dual-source, dual-energy CT from the abdomen with intravenous contrast media administration were used. A total of 17 patients (11 women, mean age 52) with a mean body mass index of 20.8 kg/cm2 were included. Simultaneously acquired images with a tube voltage of 80 kV and 140 kV were compared. Body composition was analyzed on a single slice at the L3 level. Parameters evaluated included muscle and fat attenuation (Hounsfield units [HU]), skeletal muscle index (cm2/m2), muscle area (cm2), and steatotic muscle area (cm2). Significant differences between 80 kV and 140 kV series were compared using the paired Student's t test. Results Tube potential affected muscle attenuation with an average difference of 17% between 80 kV and 140 kV series (48 HU versus 41 HU, P Conclusion Tube potential significantly affects body segmentation in contrast-enhanced CT.

Objective There is no consensus on how to estimate energy requirements after liver transplantation (LT). The aim of this study was to compare measured resting energy expenditure (REE) with predictive equations and fixed factors, and evaluate whether clinical variables were associated with REE. Methods During the period of 2011 through 2018, REE measured with indirect calorimetry and predicted by the Harris and Benedict (HB) equation was compared in patients during the first 30 postoperative days after LT. The fixed factors 25 kcal/kg, 30 kcal/kg, or 35 kcal/kg were used to calculate energy requirements. The accuracy of HB and fixed factors were evaluated with a Bland-Altman analysis and Lin’s concordance correlation coefficient. The associations of pre- and postoperative clinical variables with REE were evaluated in a multivariate regression analysis. Results A total of 143 patients were evaluated and had indirect calorimetry performed on postoperative day 6 (interquartile range: 3) in median. The mean measured REE was 1950 ± 461 kcal (range, 720–3309 kcal) or 24.5 ± 6.1 kcal/kg body weight. Large limits of agreements were observed in the Bland-Altman analyses for both HB and fixed factors. HB was closer than fixed factors with a positive concordance (concordance correlation: 0.350; 95% confidence interval, 0.248–0.445) and Pearsons r2 = 0.261. Measured REE was significantly associated (P Conclusions The low accuracy of HB and fixed factors suggests risks of both under- and overfeeding of individual patients if energy requirement is only based on calculation. REE measurement is recommended after LT to secure accurate and safe nutritional therapy.