Radiographic manifestations of extrinsic processes involving the bowel.

Extrinsic processes affecting the bowel are frequently mistaken for intrinsic gastrointestinal disease. However, extrinsic involvement of bowel produces morphologic changes distinguishable from those of primary diseases of bowel in most cases. These changes include (a) an intact mucosal surface, (b) mass effect, (c) fixation and angulation mucosal folds, (d) fixation and angulation of bowel loops, and (e) luminal constriction. The extrinsic process involving bowel most often encountered on barium studies is metastatic neoplasm; other causes are inflammatory disease, adhesions, and endometriosis. Although the radiographic manifestations of extrinsic processes affecting bowel are nonspecific, when correlated with clinical information they may permit an astute diagnosis.