Comparative evaluation of plain films, ultrasound and CT in the diagnosis of intestinal obstruction

Background: There are limited studies in the literature comparing plain radiography, US and CT in the evaluation of intestinal obstruction. We carried out this prospective study to compare the relative efficacies of these three imaging techniques in patients with intestinal obstruction. Material and Methods: Thirty-two patients presenting with clinical suspicion of intestinal obstruction were subjected to plain radiography, US and CT and the findings were compared with reference to the presence or absence of obstruction the level of obstruction and the cause of obstruction. The final diagnosis was obtained by surgery (n = 25), or by contrast studies and/or clinical follow-up in those who were treated conservatively (n=7). Results: Out of 32 patients, 30 had mechanical intestinal obstruction (22 had small bowel obstruction and 8 had large bowel obstruction). Of the remaining 2 patients, 1 had adynamic ileus and the other had a mesenteric cyst. CT had high sensitivity (93%), specificity (100%) and accuracy (94%) in diagnosing the presence of obstruction. The comparable sensitivity, specificity and accuracy were, respectively, 83%, 100% and 84% for US and 77%, 50% and 75% for plain radiography. The level of obstruction was correctly predicted in 93% on CT, in 70% on US and in 60% on plain films. CT was superior (87%) to both US (23%) and plain radiography (7%) in determining the aetiology of obstruction. Conclusion: CT is a highly accurate method in the evaluation of intestinal obstruction especially for determining the level and cause of obstruction and should be the technique of choice when clinical or plain radiographic findings are equivocal.