Colon cutoff sign

Excerpt

The “colon cutoff” sign, originally described on standard radiographs of the abdomen and now extended to computed tomography (CT) scanogram (Fig. 1), is a description of dilated, air-filled transverse colon with nonvisualization of colonic air beyond it, producing an abrupt cutoff of colonic gas at splenic flexure [1]. It was originally described in the presence of pancreatitis and is not an uncommon association with pancreatitis [2]. This appearance occurs in acute pancreatitis, when inflammatory exudates extend across the lateral end of transverse mesocolon into the phrenicocolic ligament with consequent spasm or mechanical obstruction at the level of splenic flexure. The intraperitoneal transverse colon is dilated due to changes at the splenic flexure as well as the adynamic ileus associated with pancreatitis. The CT sections in this patient with acute pancreatitis showed mildly bulky pancreas, peripancreatic fat stranding, and perirenal fascia thickening and ruled out other causes of colonic narrowing (Fig. 2). Pancreatic and gastric cancer, splenic artery hemorrhage, abdominal aortic aneurysm rupture, and ureteric rupture can also produce a similar appearance of colon cutoff apart from the neoplastic and inflammatory conditions of the splenic flexure [2, 3]. Though pancreatitis is the most common cause of the colon cutoff sign, a differential diagnosis should be kept in mind when the sign is encountered.

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