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


Medicine & Science in Sports & Exercise: July 2014 - Volume 46 - Issue 7 - p 1462–1465
doi: 10.1249/MSS.0000000000000238
SPECIAL COMMUNICATIONS: Methodological Advances

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.

Purpose: 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).

Methods: 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.

Results: 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.

Conclusions: When interpreting VAT results with the iDXA in severely obese populations, clinicians should be aware of the precision error for this important clinical parameter.

1Department of Kinesiology and Physical Education, McGill University, Montreal, QC, CANADA; and 2Bariatric Surgery, McGill University Health Center, Montreal, QC, CANADA

Address for correspondence: Ross Andersen, Ph.D., Department of Kinesiology, McGill University, 475 Pine Ave., West, Montreal, QC, Canada H2W 1S4; E-mail:

Submitted for publication July 2013.

Accepted for publication December 2013.

© 2014 American College of Sports Medicine