大腸アフタ様病変のX線学的鑑別診断―アフタ様病変のみから成るCrohn病と他疾患との鑑別を中心に

Radiographic Differential Diagnosis of Aphthoid Lesions of the Colon: Focused on Crohn's Disease with Aphthoid Lesions Alone

要旨　内視鏡検査で診断された大腸アフタ様病変68例（アフタ様病変のみから成るCrohn病18例，腸型Behget病3例，悪性リンパ腫/ATL4例，薬剤性大腸炎6例，アメーバ赤痢4例，エルシニア腸炎11例，キャンピロバクター・サルモネラ腸炎4例，アフタ様大腸炎18例）の注腸X線所見を分析し，そのX線学的鑑別について検討した．そのX線所見は，Ⅰ型：直径1～2mmの透亮像が多発（4例），Ⅱ型：直径1～2mmのバリウム斑が多発（8例），Ⅲ型＝中心に微小バリウム斑を有する直径1～2mmの透亮像が多発(20例)，Ⅳ型：中心に直径1～2mmのバリウム斑を有する1～3mmの透亮像が多発（15例），Ⅴ型：中心に直径1～2mmのバリウム斑を有する2～5mmの透亮像が多発（21例），の5型に分類できた．アフタ様病変のみから成るCrohn病では，13例（72％）がⅣないしⅤ型のX線パターンを示し，14例（78％）に直径3mm以上のびらんないし小潰瘍が認められ，うち6例（33％）は縦走傾向の配列を示した．腸型Behcet病，悪性リンパ腫/ATL，薬剤性大腸炎，アメーバ赤痢でも同様なX線パターン（Ⅳ型，Ⅴ型）を高率に示したが，病変の分布，直径3mm以上のバリウム斑の有無，縦走配列の有無などに着目すれば，Crohn病と他疾患とのX線像のみからの鑑別もある程度可能と考えられた．また病変の密度が最も高い部分の3cm四方（9cm²）の病変数を計測することによって，客観的に病変密度を評価でき，鑑別診断に役立つことが示唆された．したがって，大腸アフタ様病変の鑑別診断上，注腸二重造影は極めて有用な検査法であると考えた．

　The double-contrast barium enema findings were analyzed from the differential diagnosis standpoints in 68 patients with endoscopically proved aphthoid lesions of the colon. The diagnosis of the patients were as follows: 18 cases of Crohn's disease with aphthoid lesions alone, 3 cases of intestinal Behget's disease, 4 cases of systemic malignant lymphoma, 11 cases of Yersinia enterocolitica colitis, 4 cases of Campylobacter or Salmonella colitis, and 18 cases of aphthoid colitis. Radiologic findings were classified into the following five groups:

　1) type Ⅰ, multiple minute (1-2 mm in size) radiolucencies (4 cases, Fig. 1);

　2) type Ⅱ, multiple minute (1-2 mm in size) barium flecks as stippled appearance (8 cases, Fig. 2);

　3) type Ⅲ, multiple minute (1-2 mm in size) radiolucencies with central barium flecks (20 cases, Fig. 3);

　4) type Ⅳ, multiple small (1-3 mm in size) radiolucencies with central barium flecks (1-2 mm in size) (15 cases, Fig. 4);

　5) type Ⅴ, multiple large (2-5 mm in size) radiolucencies with central barium flecks (1-2 mm in size) (21 cases, Fig. 5).

　In Crohd's disease with aphthoid lesions alone, type Ⅳ or Ⅴ radiographic pattern with large (over 3 mm in size) barium flecks being arranged in longitudinal direction was common. Although the other diseases such as intestinal BehGet's disease, systemic malignant lymphoma, ATL, drug-induced colitis and amebic colitis showed the similar radiographic patterns (type Ⅳ or Ⅴ ), barium flecks were smaller and not arranged in longitudinal direction. The common radiologic patterns in Yersinia enterocolitica, Campylobacter, and Salmonella colitis, on the other hand, were type Ⅱ orⅢ.

　The number of aphthoid lesions per 9 cm square were directly counted on the x-ray film to evaluate their density. The density of lesions of Crohn's disease was lower than that of intestinal Behget's disease, systemic malignant lymphoma, and ATL, but was higher than that of Yersinia enterocolitica, Campylobacter and Salmonella colitis.

　These results suggest that the double-contrast barium enema is useful for differential diagnosis of aphthoid lelions of the colon.