EFFICACY OF CT IN DISTINGUISHING SMALL-BOWEL OBSTRUCTION FROM OTHER CAUSES OF SMALL-BOWEL DILATATION

OBJECTIVE. Dilatation of the small bowel is a common finding on plain abdominal radiographs. In such cases, it is often difficult to determi ne if the cause of the dilatation is small bowel obstruction, paralyti c ileus, or another intraabdominal disorder. Accordingly, we studied t he efficacy of CT in making this distinction. MATERIALS AND METHODS. T he medical records of 75 patients with small-bowel dilatation seen on CT scans (more than three segments > 2.5 cm in diameter) were reviewed . The patients were divided into three groups (obstruction [27 patient s], other surgical diagnosis [16 patients], and no surgery [32 patient s]) on the basis of clinical course, findings at surgery, or both. CT scans were retrospectively evaluated by two gastrointestinal radiologi sts who did not know the results of the chart review. They evaluated t he images with regard to the following specific criteria for obstructi on: presence/continuity of duodenal, small-bowel, and colonic dilatati on; presence of air-fluid levels; amount of intestinal fluid; presence of prestenotic dilatation; presence of transition zone; and cause of obstruction. In addition, each radiologist gave an overall impression regarding the presence or absence of obstruction (criteria not specifi ed to the observers) and its site, or other cause of bowel dilatation. The CT interpretations of each of the radiologists were compared with the patients' subsequent clinical course. RESULTS. Observer A was cor rect in 89%, 88%, and 72% of cases in the obstruction, other surgical diagnosis, and no surgery groups, respectively. Observer B was correct in 78%, 81%, and 69% of cases in the obstruction, other surgical diag nosis, and no surgery groups, respectively. Observer agreement regardi ng the proposed criteria for obstruction ranged from 65% to 91%. For b oth observers, only the presence of continuous small-bowel dilatation, prestenotic dilatation, and a transition zone correlated significantl y with the presence of small-bowel obstruction. CONCLUSION. CT can be a useful test for evaluating small-bowel dilatation and can aid both t he diagnosis of small-bowel obstruction and its differentiation from o ther conditions resulting in small-bowel dilatation.