早期胃癌の深達度診断─X線造影像を用いた深達度診断

Methods for the Diagnosis of Early Gastric Carcinoma Invasion by Gastrography

要旨●胃癌の深達度診断をX線検査の視点から述べた．X線造影像による深達度診断では，癌浸潤によって生じた胃壁の肥厚と硬化といった癌浸潤に直接結びつく所見を“因果関係に基づく所見（癌浸潤の直接所見）”という．これ以外の画像所見で癌浸潤と統計的・間接的につながる所見を“相関関係に基づく所見（癌浸潤を間接的に推測する所見）”という．陥凹型胃癌では，胃壁の肥厚・硬化・粘膜ひだの形態などが癌浸潤との因果関係を示す所見である．隆起型胃癌は腫瘍が粘膜固有層で上方へ増殖し，因果関係に基づく所見を覆い隠すため深達度診断が難しい．そこで隆起型では，病変の大きさ・肉眼型（0-IIa型，0-I型あるいは1型）・組織型などの相関関係を示す所見も合わせて病変の深達度を推測する．X線造影像を用いた深達度診断には，描出された肉眼像と病理組織所見を関連づけることが重要である．

　This article reviews how to diagnose the invasion level of gastric carcinoma from the viewpoint of gastrography. We divide gastrographic findings into the causal findings（direct findings）and the correlational findings（indirect findings）for carcinoma invasion. In the case of depressed type cancer, to recognize causal findings such as thickness or rigidity of the gastric submucosal layer and the feature of mucosal fold are useful for diagnosing carcinoma invasion. On the other hand, in the case of protrusive type cancer it is difficult to diagnose the depth of carcinoma invasion, because the causal findings are obscured by the cancerous growth on the mucosal surface layer. In those cases we predict the carcinoma invasion by the correlational findings such as lesion size, macroscopic feature (flat elevation or dome-shaped）and histological type of the cancer. We believe that the diagnosing method of gastrography is based on the relationship between macroscopic features and pathological findings of gastric carcinomas.