Precision of the iDXA for Visceral Adipose Tissue Measurement in Severely Obese Patients

Abstract

A new measurement tool, the automated software CoreScan, for the GE Lunar iDXA, has been validated for measuring visceral adipose tissue (VAT) against computed tomography in normal-weight populations. However, no study has evaluated the precision of CoreScan in measuring VAT among severely obese patients. The purpose of the study was to evaluate the precision of CoreScan for VAT measurements in severely obese adults (body mass index > 40 kg·m(-2)). A total of 55 obese participants with a mean age of 46 ± 11 yr, body mass index of 49 ± 6 kg·m(-2), and body mass of 137.3 ± 21.3 kg took part in this study. Two consecutive iDXA scans with repositioning of the total body were conducted for each participant. The coefficient of variation, the root-mean-square averages of SD of repeated measurements, the corresponding 95% least significant change, and intraclass correlations were calculated. Precision error was 8.77% (percent coefficient of variation), with a root-mean-square SD of 0.294 kg and an intraclass correlation of 0.96. Bland-Altman plots demonstrated a mean precision bias of -0.08 ± 0.41 kg, giving a coefficient of repeatability of 0.82 kg and a bias range of -0.890 to 0.725 kg. When interpreting VAT results with the iDXA in severely obese populations, clinicians should be aware of the precision error for this important clinical parameter.