Computed tomography features of the colitides

Infectious and inflammatory colitides are becoming more prevalent for a variety of reasons: 1) the increasing incidence of Crohn's disease, 2) the indiscriminate use of antibiotics, 3) the increased global travel and immigration from developing countries, and 4) immunosuppression resulting from acquired immunodeficiency syndrome (AIDS), chemotherapy, and organ and bone marrow transplantation. Patients with colitis frequently present with nonspecific symptoms such as abdominal pain, and CT is often the first imaging study ordered during their evaluation. By virtue of its ability to directly image pathologic changes in the bowel wall, serosa, surrounding mesentery, and peritoneum, CT can provide crucial information for accurate diagnosis and prompt management of patients with infectious and inflammatory colitis. This article describes the CT features of the various colitides and provides differential diagnostic guidelines.