The use of CT is highly effective in confirming large bowel obstruction and identifying the site and cause of obstruction, according to a recent study conducted by researchers at the University of South Manchester in Manchester, UK.
There is very little published evidence regarding the diagnostic efficiency of CT in large bowel obstruction (LBO), said Sathi Sukumar, MD, lead author of the study. Large bowel obstruction is a common clinical problem and plain films have been shown to be unreliable. Contrast enemas, the conventional way of investigating LBO is invasive, gives only limited information and is sometimes technically not possible and difficult to interpret, said Dr. Sukumar.
The study consisted of 42 patients who were identified for follow-up after LBO, large bowel dilatation or pseudo-obstruction was noted. On CT, 31 patients were diagnosed with large bowel obstruction, 8 with pseudo-obstruction and 3 were indeterminate. Of the 31 cases that were diagnosed with LBO, 27 were confirmed by surgery or endoscopy. Of the eight patients with pseudo-obstruction, no surgical/endoscopic intervention was required and follow-up confirmed pseudo-obstruction. The study showed that of the three patients with indeterminate CT, two were later confirmed as carcinomas and the other had a negative laparotomy.
According to the study, causes of large bowel obstruction varied from common conditions such as carcinoma, volvulus, and diverticular stricture to rare causes such as hernias, inflammatory stricture and gallstone obstruction at unusual sites. The sensitivity and specificity of CT in diagnosing LBO was 94% and 100%.
The results of this study could simplify the diagnostic process dramatically. A large number of patients in our study were frail or unwell, so it is particularly important in this group that diagnosis is achieved with the least invasive and quickest method possible, said Dr. Sukumar. Previously and even now, at some centers contrast enema is used and this can be technically difficult and highly unpleasant in this group of patients. CT in this situation is performed with no bowel preparation and can be done quickly and easily so, he said.
For the referring physician, CT not only confirms or excludes the diagnosis of large bowel obstruction; it also gives additional information which is important for management, such as impending perforation or perforation. Early intervention in these patients will reduce morbidity and even save lives, added Dr. Sukumar.
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American Roentgen Ray Society