OBJECTIVE. The purpose of this study was to determine the prevalence and demographic distribution of colonic diverticulitis (CD) and alternative diagnoses (AD), as well as the diagnostic accuracy of MDCT in patients with suspected CD. MATERIALS AND METHODS. This study retrospectively included 1069 patients (560 women) undergoing MDCT for the evaluation of suspected CD. The prevalence of CD and AD was determined and the diagnostic accuracy of MDCT calculated. The final clinical diagnosis derived from the discharge report served as the standard of reference. Prevalence of diagnoses by age, sex, and admission status were compared using Cochran-Armitage, chi-square, and Fisher exact tests. RESULTS. Prevalence of CD was 52.5% (561/1069) and of AD was 39.9% (427/1069). In the remaining 7.6% (81/1069) no final clinical diagnosis was established. The most frequent AD were appendicitis (12.6%, 54/427), infectious colitis (10.5%, 45/427), infectious gastroenteritis (8.2%, 35/427), urolithiasis (6.1%, 26/427), and pyelonephritis (4.9%, 21/427). The prevalence of diverticulitis and AD varied statistically significantly according to both age (p < 0.001) and admission status (p < 0.001). Also, the prevalence of the 10 most frequent specific AD varied statistically significantly according to sex (p = 0.022). CT had a sensitivity and specificity of 99.1% and 99.8% for diagnosing CD and 92.7% and 98.8% for AD, respectively. CONCLUSION. In about 40% of patients with suspected diverticulitis a broad spectrum of AD is causative for symptoms. MDCT provides high diagnostic accuracy in the diagnosis of diverticulitis and AD. The prevalence of diagnoses is related to admission status and demographic data; in particular age-related AD have to be considered in patients with clinically suspected diverticulitis.
