Acute left colonic diverticulitis - Compared performance of computed tomography and water-soluble contrast enema - Prospective evaluation of 420 patients

PURPOSE: The most valuable radiologic examination to be done initially when acute left colonic diverticulitis is suspected is still a matter of contro versy. This study compares the performance between water-soluble contrast e nema and computed tomography. METHODS: From 1986 to 1997, all patients admi tted in our emergency center with clinically suspected left-colonic diverti culitis had a contrast enema and a computed tomography within 72 hours of t hc:ir admission, unless clinical findings required immediate laparotomy. Th ey were prospectively included in the study if one or both radiologic exami nations showed signs of acute diverticulitis or diverticulitis was surgical ly removed and histologically proven or both. Diverticulitis was considered moderate when computed tomography showed localized thickening of the colon ic wall (5 mm or more) and inflammation of pericolic fat and contrast enema showed segmental lumen narrowing and tethered mucosa; it was considered se vere when abscess or extraluminal air or contrast or all three were observe d on computed tomography and when one or both of the last two signs were se en on contrast enema. Of 542 patients, 420 who had both computed tomography and contrast enema entered the study. RESULTS: The performance of computed tomography was significantly superior to contrast enema in terms of sensit ivity (98 vs. 92 percent; P = 0.01), which was calculated from patients who had their colon removed and whose diverticulitis was histologically proven , and in the evaluation of the severity of the inflammation (26 vs. 9 perce nt; P = 0.02). Moreover, of 69 patients who had an associated abscess seen on computed tomography, only 20 (29 percent) had indirect signs of this com plication on contrast enema. CONCLUSIONS: In the diagnostic evaluation of a cute left-colonic diverticulitis, computed tomography should be preferred t o contrast enema as the initial radiologic examination because of its stati stically significant superiority in sensitivity and for its significantly b etter performance in the detection of severe infection, especially when an abscess is associated with the disease.