Visceral adipose tissue in obesity: A comparison between DXA and MRI measures matched for anatomical location

Introduction: Visceral adipose tissue (VAT) accumulation is associated with an increased risk of cardiovascular and metabolic disease in individuals. VAT can be accurately measured by magnetic resonance imaging (MRI); however, this technology is costly and time consuming. Dual X-ray absorptiometry (DXA) presents an alternate method to estimate VAT. Traditionally, VAT measurements using DXA and MRI are taken at different anatomical locations. Although these methods correlate, their comparative accuracy remains unconfirmed. This study aimed to compare VAT volume measurements between DXA and MRI at matched anatomical locations, hypothesizing that the two methods would yield similar results Methods: A total of fifty-one MRI and DXA scans were analyzed from participants with obesity and without diabetes (18-65 years, BMI range of ≥30 to ≤55 kg/m 2 ). VAT was measured at the L3 vertebral body region by manual manipulation of the android region of interest (ROI) within the DXA scan (Hologic Inc., Marlborough, MA, USA), and manual segmentation of the MRI-VAT (Siemens Prisma, Erlangen, Germany). MRI-VAT was expressed as total segmented volume and as fractional volume (corrected for the fat fraction in each voxel). Paired t-tests assessed differences between the DXA-VAT and MRI-VAT volumes. Pearson’s correlation coefficients were computed comparing VAT measures from DXA and MRI. Bland-Altman tests assessed magnitude of bias and 95% limits of agreement between measures. Data were analyzed using RStudio version 4.4.1, and significance was set at p<0.05. Results: There were no significant differences between DXA-VAT volume and MRI-VAT total volume (780.9±251.5mL vs. 727.9±318.0mL, p=0.088). However, there was significant (p=0.014) difference between DXA-VAT volume and MRI-VAT fractional volume (780.9±251.5mLvs. 640.8±311.5L). DXA-VAT volume and MRI-VAT total volume showed a positive and strong correlation (R=0.731, p<0.001), and DXA-VAT volume and MRI-VAT fractional volume showed similar values (R=0.737, p<0.001). The Bland-Atman analysis showed a positive bias (+53.04cm 3 ) of DXA-VAT volume relative to MRI-VAT total volume and good overall limits of agreement (LoA= 479.93, -373.84). Similar agreement was observed between a positive bias (+140.1cm3) of DXA-VAT volume and MRI-VAT fractional volume with good LoA (554.6, -247.3). Conclusion: When comparing VAT measurements at the L3 vertebral level, we found strong agreement between DXA and MRI VAT volume measurements, though DXA VAT were consistently higher than MRI VAT measurements. Study was supported by UMN CTSA Award (UM1TR004405-01A1) Center for Advancing Translational Sciences and NIH (R01DK124484 to LSC, P41EB027061, S10OD017974 for MRI support). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.