A PROSPECTIVE-STUDY OF ABDOMINAL COMPUTERIZED-TOMOGRAPHY AND COLONOSCOPY IN THE DIAGNOSIS OF COLONIC DISEASE IN AN ELDERLY POPULATION

Objective: The aim of this prospective study was to compare the accura cy of abdominal computed tomography (CT) and colonoscopy in diagnosing colonic pathology in an elderly population. Methods: Patients over th e age of 70 for whom an outpatient diagnostic colonoscopy had been req uested, were invited to attend for a CT scan of the abdomen following oral colonic preparation. CT was carried out within 1 month of the col onoscopy and all images were evaluated by a single consultant radiolog ist with no prior knowledge of the colonoscopy result. Results: Of 72 patients who fulfilled entry criteria and attended for colonoscopy, 55 (29 female) had abdominal CT of the abdomen (mean age 76.6 years, ran ge 70-92). Colonoscopy was successful in 67% of cases and the followin g colonoscopic diagnoses were made: diverticular disease (26), normal (14), colonic carcinoma (6), polyps (9) colitis (2) and angiodysplasia (1). There was agreement between colonoscopic and CT diagnoses in 38 patients (69%) including all those with carcinoma of the colon. There was disagreement in 12 patients with diverticular disease, CT missed t hree polyps in three patients and angiodysplasia in one patient. CT pr ovided additional important information in 9 patients: gastric leiomyo sarcoma (1), aortic aneurysm (1), absence of metastases (3), liver met astases (2), cirrhosis and portal hypertension (1) and a large pleural effusion (1). One patient thought to have a carcinoma of the colon by both techniques was subsequently found to have a diverticular mass at laparotomy. Two patients undergoing colonoscopy had colonic perforati ons and one of these died. Conclusion: CT may provide an alternative t o colonoscopy in diagnosis of colonic disease in the elderly populatio n.