（1）X線検査

Diagnostic Imaging for Early Gastric Cancer─Further Examination for Assessment of Depth of Invasion（Methods and Diagnostic Capability） : X-ray Examination

要旨　過去3年間に慶應義塾大学病院で外科的あるいは内視鏡的に切除された胃癌症例508例554病変〔M癌243病変，SM癌162病変（SM1 43病変，SM2 119病変），MP以深癌149病変〕のX線による深達度診断を検討した．それぞれの正診率はM 91.3％，SM 79.3％，MP以深 89.9％で，術前にSM1とX線的に診断した症例はなかった．早期胃癌の8割を占める陥凹型のSM以深への浸潤は，胃壁の肥厚，伸展不良および壁硬化が参考になった．X線でこれらの所見を表わす方法として，二重造影法では病変部における造影剤の厚さを変えることによって肥厚部の厚さや輪郭を表わすと同時に，肥厚部の表面や辺縁の性状を描出して，その肥厚が粘膜の増殖によるものか粘膜下の肥厚かを鑑別すること，圧迫法では圧迫の強さを変えることによって，肥厚部の性状とともに硬さを知ることが正確な診断につながると考えられた．X線で深達度診断を的確に行うためには，二重造影法および圧迫法を駆使するとともに，どのような所見を表わすかという目的意識を持って検査にのぞむことが重要と思われた．

　We investigated assessment of depth of invasion using X-ray examination in 508 cases with 554 gastric carcinomas─intramucosal（M, n＝243 lesions）, submucosal（SM1, n＝43 lesions ; SM2, n＝119 lesions）, and deeper than the lamina propria mucosa（MP, n＝149 lesions）─resected by endoscopy or surgery at Keio University over the past 3 years. The rates of correct diagnosis were as follows : M,91.3% ; 79.3% ; MP,89.9% ; no cases of SM1 carcinoma were detected on X-ray examination.

　The features of thickening, decreased extensibility, or sclerosing of the gastric wall were useful findings to evaluate invasion deeper than the SM layer among depressed type lesions, which account for approximately 80% of cases of early gastric cancer. To demonstrate gastric characteristics by X-ray with double contrast imaging, we modulated the thickness of contrast media around the lesion to estimate the height or outline of thickening, and also assess the properties of the surface or margins of carcinoma to estimate the location of thickening, i. e., the intramucosal or submucosal layer. Evaluation of properties as well as hardness of the thickened part by manipulation with the compression method provides a more accurate diagnosis. In the X-ray study, it is important to develop ways to exhibit these manifestations using compression or double contrast methods for accurate determination of the depth of invasion.