Acute colonic diverticulitis: Prospective comparative evaluation with US and CT

PURPOSE: To compare the accuracy of ultrasonographic (US) and computed tomographic (CT) findings for diagnosis of acute colonic diverticulitis. MATERIALS AND METHODS: US and CT were prospectively performed in 64 consecutive patients suspected of having acute colonic diverticulitis. Images were interpreted independently in a blinded fashion. Imaging data were compared with the final diagnosis, which was based on initial clinical and follow-up examination results (n = 64) and pathologic (n = 22), endoscopic (n = 21), and contrast enema (n = 15) examination findings. RESULTS: Final diagnosis was acute colonic diverticulitis (n = 33), other acute abdominal condition (n = 24), or unknown (n = 7). Both CT and US findings yielded 84% accuracy. US and CT findings were not statistically significant different in terms of sensitivity (85% and 91%, respectively) and specificity (84% and 77%, respectively). Positive predictive value was 85% for US and 81% for CT; negative predictive value was 84% for US and 88% for CT. When determining alternative diagnoses, US and CT findings yielded sensitivity of 33% and 50%, respectively (difference not statistically significant). CT scans depicted a small pneumoperitoneum overlooked on plain radiographs and US scans. Six pericolic abscesses were depicted with both techniques; three were depicted with CT only. CONCLUSION: US and CT findings result in similar accuracy for the evaluation of patients suspected of having diverticulitis.