People with the above symptoms are commonly studied with computed tomography, or a CT scan. The CT scan is very accurate (98%) in diagnosing diverticulitis. In order to extract the most information possible about the person's condition, thin section (5 mm) transverse images are obtained through the entire abdomen and pelvis after oral and intravascular contrast have been administered. Images reveal localized colon wall thickening, with inflammation extending into the fat surrounding the colon. The diagnosis of acute diverticulitis is made confidently when the involved segment contains diverticula. CT may also identify people with more complicated diverticulitis, such as those with an associated abscess. It may even allow for radiologically guided drainage of an associated abscess, sparing a person from immediate surgical intervention.