During the past decade, the medical and surgical treatment of ulcerative colitis has undergone dramatic advances, including the widespread use of immunomodulators, biological drugs, and restorative proctocolectomy. In order to correctly balance the risks and benefits of medical therapies and surgical procedures, there is a need for improved diagnosis of colonic disease, acute complications, extraintestinal manifestations, and early and delayed postoperative complications. Cross-sectional imaging techniques are therefore playing an increasing role in the assessment of ulcerative colitis and provide an essential complement to clinical data and endoscopy. This practical, illustrated volume on the role of cross-sectional imaging is aimed at radiologists, gastroenterologists, and surgeons who are engaged or interested in the diagnosis and care of patients with inflammatory bowel disease, particularly ulcerative colitis. After an overview of diagnostic imaging techniques, state-of-the-art assessment of colorectal inflammatory disease with CT colonography using water enema is discussed, followed by description of the plain radiographic and CT findings in patients with acute exacerbations and surgical complications. Subsequent chapters review the diagnostic findings and role of cross-sectional imaging in the assessment of sclerosing cholangitis (with emphasis on MR cholangiopancreatography), vascular complications (particularly portal and mesenteric thrombosis), associated neoplasms, such as colorectal cancer and abdominal desmoids, and perianal inflammatory disease. Normal postoperative appearances and early and delayed complications in patients treated with proctocolectomy and ileal pouch-anal anastomosis are also comprehensively reviewed.