Ultrasonography for the Evaluation of Visceral Fat and Cardiovascular Risk

Abstract

Abstract — —Visceral fat accumulation is associated with increased cardiovascular risk. Clinical evaluation of visceral fat is limited because of the lack of reliable and low-cost methods. To assess the correlation between ultrasonography and computed tomography (CT) for the evaluation of visceral fat, 101 obese 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 by ultrasonography, 1 cm above the umbilical knot, showed a high correlation with CT-determined visceral fat ( r =0.67, P <0.0001). The ultrasonograph method showed good reproducibility with an intra-observer variation coefficient of <2%. Both ultrasonograph and CT visceral fat values were correlated with 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 ultrasonography is a useful method to evaluate cardiovascular risk. A significant 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 abdominal visceral obesity. This value also identified patients with higher levels of plasma glucose, serum insulin and triglycerides and lower levels of HDL-cholesterol, which are metabolic abnormalities characteristic of the metabolic syndrome. Our data demonstrate that ultrasonography is a precise and reliable method for evaluation of visceral fat and identification of patients with adverse metabolic profile.