US of gastrointestinal tract abnormalities with CT correlation.

Ultrasonography (US) is often the first imaging study performed in patients with abdominal pain or vague symptoms related to the gastrointestinal tract. An awareness of the US appearances of diseases of the intestine is essential to achieve the proper diagnosis and to enable appropriate triage of cases. Pathologic processes that affect the intestine generally result in decreased peristalsis and bowel wall thickening, both of which tend to decrease the luminal gas content. These changes permit evaluation of the intestine and surrounding structures with transabdominal and transvaginal US. US is useful in diagnosis of infectious and inflammatory conditions, such as appendicitis, Crohn disease, diverticulitis, epiploic appendagitis, pseudomembranous colitis, small bowel obstruction, small bowel vasculitis, and celiac disease. US is also helpful in diagnosis of tumors, such as gastric cancer, bowel lymphoma, and colon cancer. Familiarity with the US appearances of diseases that affect the intestine may allow specific diagnosis based on the degree and distribution of bowel wall thickening and associated changes of the perienteric tissues.