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

Background: There are limited studies in the literature comparing plain rad iography, US and CT in the evaluation of intestinal obstruction. We carried out this prospective study to compare the relative efficacies of these thr ee imaging techniques in patients with intestinal obstruction. Material and Methods: Thirty-two patients presenting with clinical suspicio n 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 fi nal diagnosis was obtained by surgery (n=25), or by contrast studies and/or clinical followup in those who were treated conservatively (n=7). Results: Out of 32 patients, 30 had mechanical intestinal obstruction (22 h ad small bowel obstruction and 8 had large bowel obstruction). Of the remai ning 2 patients, 1 had adynamic ileus and the other had a mesenteric cyst. CT had high sensitivity (93%), specificity (100%) and accuracy (94%) in dia gnosing the presence of obstruction. The comparable sensitivity, specificit y and accuracy were, respectively, 83%, 100% and 84% for US and 77%, 50% an d 75% for plain radiography. The level of obstruction was correctly predict ed in 93% on CT, in 70% on US and in 60% on plain films. CT was superior (8 7%) to both US (23%) and plain radiography (7%) in determining the aetiolog y of obstruction. Conclusion: CT is a highly accurate method in the evaluation of intestinal obstruction especially for determining the level and cause of obstruction a nd should be the technique of choice when clinical or plain radiographic fi ndings are equivocal.