Validity of dual-energy x-ray absorptiometry for estimation of visceral adipose tissue and visceral adipose tissue change after surgery-induced weight loss in women with severe obesity

Abstract

Objective: Reliable and simple methods to quantify visceral adipose tissue (VAT) and VAT changes are needed. This study investigated the validity of dual-energy x-ray absorptiometry (DXA) compared with magnetic resonance imaging (MRI) for estimating VAT cross sectionally and longitudinally after surgery-induced weight loss in women with severe obesity.

Methods: Women with obesity (n = 36; mean age 43 [SD 10] years; 89% White) with DXA and MRI before bariatric surgery (T0) at 12 (T12) and 24 months (T24) post surgery were included. CoreScan (GE Healthcare, Chicago, Illinois) estimated VAT from 20% of the distance between the top of the iliac crest and the base of the skull. MRI VAT (total VAT) was measured from the base of the heart to the sacrum/coccyx on a whole-body scan.

Results: Mean DXA VAT was 45% of MRI VAT at T0, 46% at T12, and 68% at T24. DXA underestimated change in MRI VAT between T0 and T12 by 26.1% (0.81 kg, p = 0.03) and by 71.7% (0.43 kg, p < 0.001) between T12 and T24. The relationship between DXA VAT and MRI VAT differed between T12 and T24 (p value for interaction = 0.03).

Conclusions: CoreScan lacks validity for comparing VAT across individuals or for estimating the size of changes within individuals; however, within the limits of measurement error, it may provide a useful indicator of whether some VAT change has occurred within an individual.

Trial registration: ClinicalTrials.gov NCT00682058.

Conflict of interest statement

Competing Interest: The authors declare no competing financial interests

© 2022 The Obesity Society.

Figures

Figure 1:

Imaging output and region of interest (ROI) of DXA & MRI scans. Figure 1a: (i) a single cross-sectional image from an MRI scan at the L4-L5 vertebrae showing VAT mass in purple; (ii) Three-dimensional volume rendering in a single participant of total VAT mass (brown) before surgery (left) and 12 months post-surgery (right). Participant is positioned in the MRI scanner with arms extended above head. Figure 1b: (i) whole body DXA scan showing bone (left) and soft tissue (right); (ii) visceral and subcutaneous tissue within the DXA VAT region of interest.

Figure 2.

Scatter plot showing the relationship between MRI VAT (kg) and DXA VAT (kg) at T0, T12, and T24. The slope at T12 is significantly different from the slope at T24 (p=.03). DXA, dual-energy x-ray absorptiometry; MRI, magnetic resonance imaging; T0, before bariatric surgery; T12, 12 months after bariatric surgery; T24, 24 months after bariatric surgery; VAT, visceral adipose tissue.