IS SLICE THICKNESS FROM COMPUTED TOMOGRAPHY RELEVANT FOR BODY COMPOSITION ANALYSIS?
body composition, computed tomography, slice thickness, radiodensity, skeletal muscle, adipose tissue
Introduction: Computed tomography (CT) is a reference method to assess body composition, widely used in clinical studies. Despite its accuracy for this purpose, CT’s technical parameters are less discussed, potentially precluding adequate standardization. Slice thickness, for instance, may play an important role in CT-derived body composition results, although data is scarce. Therefore, this study aimed to evaluate the impact of different CT slice thicknesses on body composition measurements.
Methods: A cross-sectional study including healthy and young subjects (20-45 years). CT images were evaluated following a standardized protocol at five different slice thicknesses for each participant (0.6, 1.25, 2.5, 5, and 10 mm). Tissue analysis was performed using the semi-automatic mode of SliceOmatic® software (TomoVision). Paired-measures ANOVA with Tukey’s post-hoc test evaluated differences between slice thicknesses.
Results: A total of 550 slices (from 110 individuals) were analyzed (56.4% females). Radiodensity differences were observed between slice thicknesses of the intermuscular and visceral adipose tissue (DIMAT and DVAT in HU) and for the area of intermuscular adipose tissue (IMAT in cm2). Most relevant differences occurred between the thinner slices (0.6 and 1.25 mm) vs. the thickest slice (10 mm), all adjusted p-values <0.001. Differences in skeletal muscle area were not significant in any slice thickness. These results were consistent across sex- and BMI-stratified analyses.
Conclusion: Slice thickness may influence adipose compartments’ radiodensity, potentially affecting tissues’ composition analyses. Our findings reinforce the need of operational standardization for CT image acquisition parameters.