Ultrasonography for the evaluation of visceral fat and cardiovascular risk

Visceral fat accumulation is associated with increased cardiovascular risk. Clinical evaluation of visceral fat is limited because of the lack of reli able and low-cost methods. To assess the correlation between ultrasonograph y and computed tomography (CT) for the evaluation of visceral fat, 101 obes e women, age 50.5 +/- 7.7 years with a body mass index of 39.2 +/- 5.4 kg/m (2), were submitted to ultrasonograph and CT scans. Visceral fat measured b y ultrasonography, I cm above the umbilical knot, showed a high correlation with CT-determined visceral fat (r=0.67, P <0.0001). The ultrasonograph me thod showed good reproducibility with an intra-observer variation coefficie nt of <2%. Both ultrasonograph and CT visceral fat values were correlated w ith fasting insulin (r=0.29 and r=0.27, P <0.01) and plasma glucose 2 hours after oral glucose load (r=0.22 and r=0.34, P <0.05), indicating that ultr asonography is a useful method to evaluate cardiovascular risk. A significa nt correlation was also found between visceral fat by CT and serum sodium ( r=0.18, P <0.05). A ultrasonograph-determined visceral-to-subcutaneous fat ratio of 2.50 was established as a cutoff value to define patients with abd ominal visceral obesity. This value also identified patients with higher le vels of plasma glucose, serum insulin and triglycerides and lower levels of HDL-cholesterol, which are metabolic abnormalities characteristic of the m etabolic syndrome. Our data demonstrate that ultrasonography is a precise a nd reliable method for evaluation of visceral fat and identification of pat ients with adverse metabolic profile.