RADIOLOGY: GASTROINTESTINAL: GI: Case# 32899: CROHNS DISEASE C SBO @ T1. This is a 29 year old female who has complained of lower abdominal pain x one day. Previous ultrasound shows dilated thickened bowel with questionable appendicitis. The small bowel is dilated and fluid filled to the terminal ileum, where a 6 cm length of thickened bowel is seen with little appreciable lumen with streaky changes to the surrounding fat. No other masses or lymphadenopathy is seen. The appendix is not definitely visualized. A small amount of ascites is seen, and the colon is not dilated. Crohns Disease, an idiopathic chronic inflammatory disease, most commonly involves the ileocecal portion of the bowel or the colon, although it is possible for any portion of the gastrointestinal tract to be affected. Morphologically, Crohns disease is characterized by thickening of involved segments with narrowing of the lumen, linear ulceration of the mucosa, submucosal edema with elevation of the surviving mucosa producing a "cobblestone" appearance, skip lesions, possible discrete noncaseating granulomas, and submucosal fibrosis. Clinical manifestations include abdominal pain, diarrhea, malabsorption, fever, intestinal obstruction resulting from stricture, and fistulae between loops of intestine, and between the intestine, bladder, vagina, and skin. CT findings include circumferential thickening of the bowel wall up to 1 to 2 cm, a low density inner ring of submucosal edema, diffuse haziness and increased density of messenetric fat, "skip areas" of normal bowel interspersed between diseased segments, fistulae and sinus tracts between bowel loops, or to the bladder, adjacent muscle, or the skin surface, and messenteric abcscesses containing fluid, air, or contrast material.