The Colon Cutoff Sign

The colon cutoff sign refers to the abrupt termination of gas within the proximal colon at the level of splenic flexure, seen on abdominal radiographs, CT, and barium enema in patients with acute pancreatitis. Usually, decompression of the distal colon is also seen.

It is thought that inflammatory mediators from acute pancreatitis extend into the phrenicocolic ligament, resulting in spasm and/or mechanical narrowing of the colon as it returns to the retroperitoneum. The effect is accentuated by focal ileus from the same inflammatory mediators.

The phrenicocolic ligament (sustentaculum linealis) is a peritoneal fold that extends from the splenic flexure to the diaphragm at the level of the eleventh rib.

Reference

Pickhardt PJ. The Colon Cutoff Sign. Radiology. 2000 May;215(2):387-9.