Intestinal obstruction is a state in which the intestinal contents cannot function normally or the passage is impaired. According to the cause of obstruction, it can be divided into mechanical intestinal obstruction, dynamic intestinal obstruction and hemodynamic intestinal obstruction; according to the presence or absence of blood flow obstruction of intestinal wall, it can be divided into simple intestinal obstruction and strangulated intestinal obstruction; according to the height of the obstruction site, it can be divided into high intestinal obstruction and low intestinal obstruction. So how to make a diagnosis? Please see the following etiological diagnosis analysis: etiological diagnosis The etiology of intestinal infarction is complex and diverse, such as intestinal adhesions, primary or secondary tumors, Crohn’s disease, vascular lesions, parasites, bold stones, fecal masses, abdominal hernias, chronic colonic diverticulitis, intussusception, intestinal torsion and so on. CT can play a greater role in the pathological diagnosis of obstruction compared to abdominal plain films. Intestinal adhesions account for about 1/3 of obstruction cases, and the use of the window-width window technique can well show the cords of adhesions, their location and relationship with the surrounding intestinal canal and abdominal wall. For intestinal obstruction caused by tumor, CT can generally accurately show the site of tumor and its invasion range to the surrounding tissues and organs. Enhancement scan is very important for diagnosis, and attention should be paid to look for other signs of tumor, such as liver metastasis, lymph node enlargement, infiltration of surrounding intestinal canal and organs, etc. In intestinal obstruction caused by inflammatory stenosis, the stenosis of intestinal lumen is more obvious than that caused by tumor on CT, and the lumen of the stenotic segment may appear as thin lines, but the contour of the intestinal lumen is relatively smooth; the thickening of the intestinal wall is mostly mild to moderate, and the contour of the intestinal wall is more regular; inflammatory stenosis may form multiple stenoses and dilated intestinal segments, while tumor is often a single stenosis. Gallstone intestinal obstruction is less common, and its CT manifestation has certain characteristics, which is called Rigler’s triad: (1) pneumatization and dilatation of intestinal collaterals, (2) ectopic calcified gallstones in the lower abdomen, and (3) small amount of gas in the gallbladder or bile duct. In the diagnosis of intestinal infarction by CT, the following issues should also be considered: the presence or absence of intra- and extra-abdominal hernias; the presence of more than two etiologies (e.g., adhesions with intestinal torsion or abdominal hernia); the presence of more than two sites of intestinal obstruction (e.g., multiple stenoses of the intestine due to tuberculosis, extensive adhesive intestinal obstruction, etc.); and the presence of congenital intestinal malformations.