The radiographic "colon cut-off sign" in acute pancreatitis.

Abstract

The clinical differential diagnosis of the “acute abdomen” is well known. The actual diagnosis, however, is often fraught with much misgiving. Many times the clinician is confronted with the necessity of watchful waiting and careful neglect at one end of the spectrum and the vigorous diagnostic exploratory laparotomy at the other. In this situation it is the place of the radiologist to direct attention toward a particular diagnosis, if possible, and suggest further procedures which might be helpful in attaining that end. Acute pancreatitis is one cause of the acute abdominal syndrome in which radiology can contribute a great deal toward the diagnosis. This is particularly important, since surgical intervention should be avoided in this entity. At least twenty-three possible roentgen abnormalities have been reported as occurring in association with acute pancreatitis (12). Unfortunately, many of these are observed so infrequently or are so non-specific that they are of little diagnostic aid. Much emphasis has been placed upon the regional abnormalities of the bowel pattern in this disease. In 1950 Grollman, Goodman, and Fine (6) introduced the term “sentinel loop” for the localized ileus involving the jejunum. This is now an established radiographic sign of acute pancreatitis and has been reported as occurring in as high as 55 per cent of the cases (12). Less well known are the adynamic changes in the large bowel. Price (10), in 1956, was the first to document these changes. In reporting 3 cases, he described an “isolated gaseous distension of the ascending colon and hepatic flexure, with sharp delimitation of the gas shadow just to the left of the hepatic flexure.” This he called the “colon cut-off sign.” Many articles have since appeared in the literature referring to this colon cut-off, but often with different meaning. Stuart (13) describes an absence of gas in the mid-transverse colon in his cases. The hepatic and splenic flexures contained gas which appeared to be sharply demarcated from the central segment. Schwartz and Nadelhaft (11) reviewed 11 cases of acute pancreatitis showing the “colon cut-off sign.” They found that the splenic flexure was the most commonly narrowed area and were of the opinion that narrowing in this location with dilatation of the colon proximally is consistent with the radiographic diagnosis of pancreatitis. Recently we became aware of a rather frequent occurrence of this distal “cut-off sign” in cases of acute pancreatitis in our hospital. Over a dozen such cases were encountered in less than a year, and frequently we were able to suggest the diagnosis on the basis of the x-ray findings alone. This experience prompted us to review 93 cases of pancreatitis diagnosed in the last five years in Brooke General Hospital (Fort Sam Houston).