The usefulness of mesenterium thickness as an index of visceral fat accumulation

Visceral fat syndrome, which includes visceral fat accumulation, glucose intolerance, hyperlipidemia, and hypertension, refers to a highly atherogenic state with a cluster of risk factors secondary to visceral fat accumulation. Although X-ray computed tomography (CT) is used commonly in diagnosis of visceral fat accumulation, it is expensive and exposes the patient to radiation. Some indices obtained using ultrasonography, which is fast and easy to use, have been reported. The ratio of the maximum thickness of preperitoneal fat (P) to the minimum thickness of subcutaneous fat (S), the abdominal wall fat index (P/S), is widely used in ultrasonographic diagnosis, however, this ratio tends to vary largely according to examiners. To establish a more reliable ultrasonographic index of visceral fat accumulation, we measured the thickness of the mesenterium, and tried to examine the relation between its thickness and maximum thickness of preperitoneal fat, minimum thickness of subcutaneous fat, and abdominal wall fat index, as well as body mass index, systolic and diastolic blood pressure, and levels of serum triglyceride, high-density lipoprotein cholesterol, total cholesterol, and blood sugar. The subjects were 131 individuals, 98 males and 33 females, averaging 47.0±7.9 years, with a mean body mass index of 24.1±2.6. The mesenterium was measured with a 3.5 or 3.75 MHz convex probe by longitudinal scanning on the left side of the umbilicus of the patient in the supine position. The thickness of the mesenterium correlated positively with maximum thickness of the preperitoneal fat, abdominal wall fat index, body mass index, and levels of serum triglyceride, total cholesterol, and blood sugar, and negatively with levels of high-density lipoprotein cholesterol. When the subjects were divided into a high-M group and a normal-M group, body mass index, triglyceride level, and blood sugar levels in the high-M group were significantly higher and level of high-density lipoprotein cholesterol was significantly lower than in the normal-M group. These results suggest that the thickness of mesenteium measured by ultrasonography may be useful in the diagnosis of accumulation of visceral fat.