小腸X線造影

Radiographic Diagnosis of the Small Bowel Disease

要旨●小腸X線造影検査はバリウムの投与経路から経口法と経管法（ゾンデ法）に分類される．経口法では充盈像と圧迫像が，経管法ではバリウムに加え空気を投与することにより，充盈像，圧迫像と二重造影像が得られる．潰瘍性病変を呈する炎症性疾患のX線診断では，特に管腔変形・狭窄例において，①狭窄の形態，②狭窄と腸間膜の位置関係，③周囲粘膜の随伴所見，の解析が鑑別診断に有用となる．びまん性病変を呈する疾患は，X線上，皺襞肥厚と顆粒状粘膜の組み合わせを呈することが多く，両所見の解析が診断に重要である．腫瘍性病変の鑑別診断には，①SMT様所見の有無，②管外性発育傾向の有無，③狭窄部の両端のoverhanging edgeの有無，④壁伸展不良所見の程度，などの解析が有用である．生理的に管腔が狭い小腸では，狭窄合併例での内視鏡的アプローチには限界があり，X線造影検査の併用が病変の全体像の把握に有用となる症例が少なくない．二重造影像は切除標本肉眼像，病理組織像との対比に有用であるが，特に管腔変形・狭窄所見は，内視鏡検査では得られない輪郭線から成り，その解析は鑑別診断に極めて有用で，質的診断能の観点から内視鏡検査を凌駕する可能性がある．

　Small bowel radiography is classified according to the barium administration method into the per-oral and per-intestinal methods（sonde method）. Barium-filled and compression images are obtained using the per-oral method ; the per-intestinal method also obtains barium-filled and compression images, but it also obtains double-contrast images by administering air in addition to barium. In the radiographic diagnosis of inflammatory disease with ulcerative lesions（particularly for cases with luminal deformity and stenosis）, the analysis of（1）the morphology of the stenosis area,（2）the positional relationship of the stenosis and mesentery, and（3）the associated findings of the surrounding mucous membrane are useful for differential diagnosis. In diseases with diffuse lesions, most cases present with mucosal fold hypertrophy, combined with granular mucosa on radiography ; the analysis of both findings is important for diagnosis. For differential diagnosis of neoplastic lesions, it is useful to analyze（1）the presence or absence of SMT（submucosal tumor）-like findings,（2）the presence or absence of a tendency for extraluminal growth,（3）the presence or absence of an overhanging edge at both ends of the stenotic area, and（4）the degree of poor distensibility of the wall. The endoscopic approach is limited in cases with concurrent stenosis when the lumen of the small intestine is physiologically narrow. The concurrent use of barium radiography is often useful for obtaining an image of the entire lesion. In particular, findings of luminal deformities and stenosis on barium radiography depict contour lines, which cannot be obtained on endoscopy by intraluminal observation and are thus extremely useful for differential diagnosis. Also, from the perspective of diagnosability, it can be superior to endoscopic examination.