Best single-slice measurement site for estimating visceral adipose tissue volume after weight loss in obese, Japanese men

Abstract

Background: Although the measurement site at L4-L5 for visceral adipose tissue (VAT) has been commonly accepted, some researchers suggest that additional upper sites (i.e., L1-L2 and L2-L3) are useful for estimating VAT volume. Therefore, determining the optimum measurement site remains challenging and has become important in determining VAT volume. We investigated the influence of a single-slice measurement site on the prediction of VAT volume and changes in VAT volume in obese Japanese men.

Methods: Twenty-four men, aged 30-65 years with a mean BMI of 30 kg/m2, were included in a 12-week weight loss program. We obtained continuous T1-weighted abdominal magnetic resonance images from T9 to S1 with a 1.5-T system to measure the VAT area. These VAT areas were then summed to determine VAT volume before and after the program.

Results: Single-slice images at 3-11 cm above L4-L5 had significant and high correlations with VAT volume at baseline (r=0.94-0.97). The single-slice image with the highest correlation coefficient with respect to VAT volume was located at 5 cm above L4-L5 (r=0.97). The highest correlation coefficient between the individual changes in VAT area and changes in VAT volume was located at 6 cm above L4-L5 (r=0.90).

Conclusions: Individual measurement sites have different abilities to estimate VAT volume and changes in VAT volume in obese Japanese men. Best zone located at 5-6 cm above L4-L5 may be a better predictor of VAT volume than the L4-L5 image in terms of both baseline and changes with weight loss.

Figure 1

The variation in the correlations between the VAT (a) or SAT (b) volumes and the single-slice image areas (right) (Baseline: (□), change: (Δ)); shaded symbols (■ and ▲) indicate significantly greater correlations with volume than that for L4–L5 (Data not shown for 19–20 cm above L4–L5 in VAT, for which there were no significant correlations). (*) indicates the level of L4–L5. Measurement locations were from 3 cm below L4–L5 to 20 cm above L4–L5. n = 24. Bold indicates the highest correlation coefficient. MRI, magnetic resonance imaging. Δ, changes.