- Diverticulitis is defined as an inflammation of one or more diverticula.
- Disease is frequently mild when pericolic fat and mesentery wall-off a small perforation.
- More extensive disease leads to abscess formation.
- Fistulae to adjacent organs and the skin may develop in the presence of an abscess.
- The most common fistula is colovesicular in men.
 Imaging Findings
- Colonic and paracolic inflammation in the presence of underlying diverticula (diverticula are identified on CT scans as outpouchings of the colonic wall).
- Symmetric thickening of the colonic of approximately 4-5 mm is common.
- Enhancement of the colonic wall is commonly noted. This usually has inner and outer high-attenuation layers, with a thick middle layer of low attenuation.
- Free diverticular perforation results in the extravasation of air and fluid into the pelvis and peritoneal cavity.
- Air in the bladder in the presence of a nearby segment of diverticulitis is suggestive of a colovesical fistula.
Patient #1: CT images demonstrate diverticulitis
Patient #2: CT images demonstrate a diverticular abscess