Colonic diverticulitis: diagnostic value and appearance of inflamed diverticula-sonographic evaluation

Acute bowel inflammation frequently originates from thin-walled diverticula of the colon. Not the presence of diverticula, but the demonstration of an inflamed diverticulum, is diagnostic of diverticulitis in cases of bowel w all thickening and pericolic inflammation. The aim of this study was to inv estigate the sonographic appearance and detectability of inflamed diverticu la. One hundred seventy-five consecutive patients with clinically suspected diverticulitis under-went sonographic examination. Outpouchings from the c olonic wall centred in the pericolic inflammation were considered inflamed diverticula. Depending on the sonographic appearance they were divided into four groups: hypoechoic; predominantly hyperechoic; hyperechoic with surro unding hypoechoic rim; and hyperechoic with acoustic shadowing. Sonography showed inflamed diverticula in 79 (77%) of 102 patients with diverticulitis . Inflamed diverticula were hypoechoic in 37%, predominantly hyperechoic in 4%, hyperechoic with surrounding hypoechoic rim in 41% and hyperechoic wit h acoustic shadowing in 18% of patients. In 23 (23%) of 102 patients no inf lamed diverticulum was demonstrable. This group included 17 patients with c omplicated diverticulitis and 6 false-negative cases. An inflamed diverticu lum as a sign of diverticulitis yielded an overall sensitivity of 77% and a specificity of 99%. Sensitivity in uncomplicated disease was 96%. In patie nts with uncomplicated diverticulitis an inflamed diverticulum is a sign of diverticulitis with excellent sensitivity and specificity, usually with so litary and less frequently with more than one inflamed diverticulum being d emonstrable. In patients with complicated diverticulitis an inflamed divert iculum is often not detectable.