大腸結核のX線診断

Radiologic Diagnosis of Colonic Tuberculosis

　腸結核をX線診断することの現代的意義は2つのことがらに集約されると思われる．ひとつは，治癒しかかっている結核病変，ないしは瘢痕のX線診断を起点とする微細診断へのアプローチが可能になったことである．すなわち，活動性の結核病変（潰瘍）が現在ではきわめて少なくなってきたという事実をわれわれがうまく利用しきったことに，X線診断の進歩をみることができる．もうひとつ，現在腸結核は絶えずクローン病との鑑別診断の立場に立って論じられているという点にも，本症のX線診断に多大の意義をみいださなくてはなるまい．腸結核の瘢痕のX線診断から微細診断へのいとぐちについては，筆者が本症のX線診断の仕事に一応の区切りをつけた1955年にすでに述べたつもりである．また，この仕事が胃のびらんの診断からⅡcの診断へと急速な展開をみせたことは周知のことである．一方，大腸の微細診断は，早期胃癌の診断についての研究が一段落しはじめるころに，「fine network pattern」の概念を提唱した西沢・狩谷・吉川らによってはほぼ完成されたとみてよいであろう．

　結核とクローン病の鑑別はX線的には簡電である．というよりも，われわれは簡単にできると考えている．両者の鑑別がむずかしいというのは，ひとつにはX線診断の方向づけを病理の側が確認できないでいることであり，もうひとつは，輸入された概念であるクローン病が日本の実情に即して理解されていないことによるものである．前者のことに関していえば，X線診断を主体とする形態学的アプローチは曖昧なlaboratory criterionよりもはるかに頼りになるものだと思うのだが，病理組織学的なうらづけに欠けるという理由のために，診断上の主導権を握ることができないでいる．そして，これがまた，病理の側の独善的なMerkmal Diagnoseの是非を正せない理由にもなっている．

　Macroscopic and radiologic study of colonic tuberculosis was made, based upon 79 operated cases of inflammatory diseases of the intestine, including 47 cases of tuberculosis, 21 cases of Crohn's disease, 9 cases of ulcerative colitis and 2 indeterminate cases.

　As the first step of this study, color, and black and white pictures of the operated materials were arranged at random, and the macroscopic diagnosis was made on each case, regardless of the diagnosis before surgery. Thirty-four cases were macroscopically diagnosed as tuberculosis, including 5 cases localized in the small intestine. Of these, the final diagnosis of Crohn's disease were made on 1 case of tuberculosis involving the ileum and the right colon and 1 case of the ileum. Accuracy of the macroscopic diagnosis was 94%. On the other hand, there was 1 case of tuberculosis in the final diagnosis which was macroscopically diagnosed as Crohn's disease. In addition, there were 14 indeterminate cases on the macroscopic diagnosis which revealed “scarred area with discoloration” in the entire lesion. Of these, 3 cases were histologically diagnosed as tuberculosis because they revealed caseation necrosis either in the lesion or the lymph node. Eleven of them which histologically revealed only atrophic mucosa and fibrosis of the submucosal layer were also macroscopically diagnosed as tuberculosis because “the scarred area with discoloration” was not observed in the other inflammatory bowel diseases. The scarred area with discoloration is one of the components which constitute a tuberculous lesion in most cases.

　Generally, the radiologic diagnosis of colonic tuberculosis can be established if a combination of transverse ulcer, the scarred area with discoloration and characteristic deformity of the viscus are visualized in double contrast radiography. A transverse ulcer is usually linear or girdle-like in form and annular. The radiologic findings of the scarred area with discoloration consists of a slightly rough mucosal surface delineated as abnormal barium coating where mucosal convergence and inflammatory polyps are scattered. The deformity includes shortening and narrowing of the viscus, disappearance of the haustration, stenosis, depressed sign and pouch-formation (pseudo-diverticulum).

　Various degrees of stenosis and bilateral depression are visualized at the site of the transverse ulcer. Disappearance of the haustration is associated with the scarred area with discoloration. Pouch-formation is often visualized in the cecum.