超音波内視鏡による胃潰瘍の深さの判定

Endoscopic Ultrasonography in the Assessment of the Depth of Gastric Ulcer

要旨　胃潰瘍の深さの臨床的判定は，潰瘍病変と胃壁の粘膜層，粘膜下層，固有筋層との関係から病理学的に判定する村上の分類を基準にして行われている．超音波内視鏡は，村上の分類による深さの判定の指標となる胃壁層構造と，潰瘍の断層像を明瞭に描写可能なことから，村上の分類に準じた潰瘍の深さの臨床的判定方法として有力である．すなわち，第3層（粘膜下層）に変化が及ぶものの，断裂を認めないときはUl-Ⅱ，第3層の断裂が確認されながら，第4層（固有筋層）あるいは第5層（漿膜）の連続性が認められればUl-Ⅲ，第4，5層の断裂が確認されればUl-Ⅳと判定される．この超音波内視鏡による潰瘍の深さの判定は潰瘍治癒の難易性の予測，更には治療の選択に重要な情報を提供するものである．

　The depth of a gastric ulcer is usually classified according to Murakami's calssification, which is based on the histological relation between the depth of the ulcer and the structure of the gastric wall, such as mucosal layer, submucosal layer and muscle layer.

　Endoscopic ultrasonography can clearly visualize the structure of the gastric wall and the ulcer lesion. Therefore endoscopic ultrasonography is an excellent procedure for the judgement of the depth of a gastric ulcer.

　In case of Ul-Ⅱ ulcer where the depth is limited to the submucosa, the sonographical changes of the gastric wall's structure are limited to the central high-echo layer, which corresponds to the submucosa.

　When the depth of ulcer reaches the proper muscle layer, that is Ul-Ⅲ, the central high-echo layer is interrupted and the outermost high-echo layer, corresponding to the serosa, is intact ultrasonographically. If the outermost high-echo layer is interrupted, it indicates that the depth of the ulcer has reached the serosa, that is Ul-Ⅳ.

　Endoscopic ultrasonography for the determination of the depth of an ulcer has proved very useful, especially for the choice of the treatments of peptic ulcer.