Role of Multislice CT in Diagnosis of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD): is a chronic idiopathic disease affecting the gastrointestinal (GI) tract that is comprised of two separate, but related intestinal disorders; Crohn s disease (CD) and ulcerative colitis (UC), IBD is thought to result from an exaggerated and inappropriate immune response to gut luminal microbes in genetically, susceptible individuals who are exposed to environmental risk factors. IBD is most common in North America and western and northern Europe, where incidence rates for UC and CD range from 2.2-24.3 per 100000 person years, It is estimated that more than 1.4 million Americans and as many as 2.5-3 million, Europeans have IBD. While UC and CD share some features, the diseases are distinct. Perhaps the most important differences are that while the chronic inflammation seen in UC is limited to the large intestine and affects only the intestinal mucosa, the inflammation in CD can occur at any location(s) along the GI tract and is often transmural, predisposing patients with CD to the development of penetrating (fistulizing) and fibro stenotic (stricturing) phenotypes that are not typically seen in UC. In some cases, UC and CD are not distinguishable and a diagnosis of IBD unclassified (IBD-U) is made although clinical features of IBD-U tend to mirror those of UC Clinical manifestations of UC include diarrhea, with or without blood, abdominal pain, tenesmus, and fecal urgency, while the manifestations of CD are more variable depending on the extent and location of the GI inflammation. CD with predominantly colonic involvement often presents in similar fashion to UC whereas in small bowel CD, diarrhea and rectal bleeding are seen less frequently and symptoms, fever, fatigue and weight loss are common.