Radiographic and CT Imaging Assessment of Acute Exacerbations and Surgical Complications

Approximately 15 % of patients with ulcerative colitis experience at least one bout of acute severe colitis during their lifelong course. Diagnosed according to clinical criteria, acute severe colitis represents a serious condition that needs intensive in-hospital treatment and may lead to perform urgent colectomy if unresponsive. Currently rather uncommon, toxic megacolon is the end of the spectrum of acute severe colitis. Plain abdominal radiographs may prove useful to assess the presence and entity of colonic dilatation and the gross disease distribution. Urgent multidetector CT is increasingly used to assess patients with acute severe colitis, as it allows assessment of colonic mural thickening, stratification, dilatation, longitudinal disease extent and perivisceral changes. In selected patients water enema multidetector CT with limited or no bowel preparation may be useful to further improve assessment of acute ulcerative colitis changes, severity and extent. Furthermore, acute manifestations of ulcerative colitis may occasionally correspond to bowel perforation or to infectious superimposition with Clostridium difficile or Cytomegalovirus colitis.