Body composition evaluation with computed tomography: Contrast media and slice thickness cause methodological errors

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Vol. 59; pp. 50 - 55
• Main Authors: Morsbach, Fabian, Zhang, Yi-Hua, Martin, Lena, Lindqvist, Catarina, Brismar, Torkel
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2019; Elsevier Limited
• Subjects: Abdomen; Adipose tissue; Adipose Tissue - diagnostic imaging; Adult; Aged; Aged, 80 and over; Attenuation; Body Composition; Cancer; Carcinoma, Hepatocellular - diagnostic imaging; Composition effects; Computation; Computed tomography; Contrast agents; Contrast Media; Coronary vessels; Diagnostic Errors; Evaluation; Fat; Female; Hepatocellular carcinoma; Humans; Image contrast; Image processing; Image reconstruction; Image segmentation; Injection; Iodine; Liver cancer; Liver cirrhosis; Liver Neoplasms - diagnostic imaging; Male; Medical imaging; Medicin och hälsovetenskap; Middle Aged; Muscle; Muscle, Skeletal - diagnostic imaging; Muscles; NMR; Nuclear magnetic resonance; Patients; Perfusion; Radiation; Radiation Dosage; Retrospective Studies; Segmentation; Skeletal muscle; Skeletal muscle index; Thickness; Tomography, X-Ray Computed - methods; Germany; Skeletal muscle index; Fat; Muscle; Segmentation; Computed tomography; Body composition
• ISSN: 0899-9007; 1873-1244; 1873-1244
• DOI: 10.1016/j.nut.2018.08.001

•Different computed tomography parameters influence body composition analysis.•Contrast medium has a strong effect on the evaluation of body composition.•Slice thickness influences evaluation of body composition.•Radiation dose can be reduced without affecting body composition evaluation. 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 P < 0.001). 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 P < 0.05). 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.