Optimal radiographic work up of diverticulitis
MDCT is more than 95% accurate in the diagnosis of diverticulitis. It is superior to other modalities because it directly depicts the severity of the pericolic inflammation and the full intraperitoneal or retroperitoneal extension. It is more sensitive than a barium study in detecting abscesses and fistulas. The CT assessment of the colon is improved with adequate colonic opacification and distention with oral contrast.
The CT hallmark of acute diverticulitis is increased attenuation in the pericolic fat or “dirty fat.”. A phlegmon or abscess, possibly containing air may be seen. With perforation, air may be seen in the peritoneum or retroperitoneum. Diverticula and a thickened bowel wall are usually present, but these findings are nonspecific. The bowel wall thickening occasionally may be difficult to distinguish from colon cancer. Findings that suggest tumor include a short segment (< 10 cm), an abrupt transition zone, wall thickness larger than 2 cm, lymphadenopathy, and metastases.