小野 倫子, 谷口 信行, 紊ф召 正明, 小野口 晃, 金子 淑子, 中澤 成公, 河野 幹彦, 伊東 紘一

Tomoko ONO, Nobuyuki TANIGUCHI, Masaaki OSAWA, Akira ONOGUCHI, Syukuko KANEKO, Yoshitaka NAKAZAWA, Mikihiko KAWANO, Kouichi ITOH

自治医科大学臨床検査医学

Department of Clinical Laboratory Medicine, Jichi Medical School

キーワード : arteriosclerosis, mesenterium, ultrasonography, visceral fat, visceral fat syndrome

内臓脂肪症候群は, 内臓脂肪蓄積を基盤に, 耐糖能異常, 高血圧, 高脂血症を併せ持つ病態であり, 動脈硬化性疾患のmultiple risk factor clustering syndromeの1つとして知られている. 内臓脂肪蓄積の診断にはX線CTが用いられているが, 被爆や簡便性の問題から超音波を用いた診断法もいくつか報告されている. その中でも腹膜前脂肪の最大厚(以下P)と腹壁皮下脂肪の最小厚(以下S)の比(P/S)である腹壁脂肪指数(以下AFI)が有名であるが, 誤差が大きいなど, いくつか問題点を有している. そこで我々は, 内臓脂肪蓄積の超音波検査による新しい指標として, 腸間膜の厚さ(以下M)を測定し, Mと他の指標(P, S, AFI)及び血清脂質や血糖, 血圧との関連性について検討を行った. 対象は, 131名(男98名, 女33名, 平均BMI, 24.1±2.6; 平均年齢, 47.0±7.9歳). Mは臍左側の縦走査で, コンベックス型探触子を用いて計測した. MはP・AFI・BMI・TG・TC・BSと正, HDLと負の相関関係が認められた. 対象をM高値群とM正常群に分けると, M高値群ではBMI・TG・BSが有意に高値であり, HDLが低値であった. 以上よりＭは, 内臓脂肪蓄積の新しい指標として有用であると考えられた.

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賊7.9 years, with a mean body mass index of 24.1賊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.