Quantification of adipose tissue by MRI: relationship with anthropometric variables

TLDR

The study aimed to validate MRI as a tool for measuring total and regional adipose tissue in humans and to evaluate how anthropometric variables predict MRI‑measured adiposity. Twenty‑seven healthy men (mean age 40.8 yr, BMI 28.5, WHR 0.96) underwent whole‑body MRI, and total adipose tissue volume was calculated by linearly interpolating areas from 41 consecutive 10‑mm slices from head to toe. MRI reliably quantified total and regional adipose tissue, revealing large interindividual variability (total AT 6.9–59.3 L, subcutaneous 6.3–49.8 L, visceral 0.5–8.5 L) and showing that waist circumference explained 92 % of total AT variance, while WHR predicted visceral AT (r = 0.85) but accounted for only 12 % of visceral AT variation after adjusting for age and adiposity, with age better predicting the visceral‑to‑subcutaneous ratio.

Abstract

This study had two objectives: 1) to establish magnetic resonance imaging (MRI) as a tool for measuring total and regional adipose tissue (AT) distribution in humans and 2) to assess the relationship between selected anthropometric variables and MRI-measured AT. Twenty-seven healthy men varying in age [40.8 +/- 14.5 (SD) yr], body mass index (28.5 +/- 4.8), and waist-to-hip ratio (WHR, 0.96 +/- 0.07) participated in the study. Total AT volume was determined using a linear interpolation of AT areas obtained on consecutive slices (n = 41) taken from head to toe (10-mm thickness, 50-mm centers). The mean change for repeated measures of total AT volume was 2.9% (range 0.9-–4.3%). Large interindividual differences were observed for total AT volume (6.9–59.3 liters), subcutaneous AT (6.3–49.8 liters), and visceral AT (0.5–8.5 liters). Visceral AT represented 18.3% of the total AT. The single best predictor of total adiposity was waist circumference (R2 = 0.92). For visceral AT volume, WHR was the strongest anthropometric correlate (r = 0.85, P less than 0.01). When controlled for age and adiposity, however, WHR explained only 12% of the variation in absolute visceral AT and less than 1% of the variation in visceral-to-subcutaneous ratio. Age was a better predictor of visceral-to-subcutaneous ratio than level of adiposity or WHR. The results of this study demonstrate that MRI offers a reliable measure of regional and total AT distribution in humans and, thus, is of value as a research tool.