CT evaluation of wall thickening in the alimentary tract.

Computed tomography (CT) of the alimentary tract, when performed with adequate distention of the organ being examined and in the true axial plane, provides valuable information about the intramural or extramural extent of pathologic conditions. Neoplastic, vascular, and inflammatory diseases can all result in wall thickening of the alimentary tract. Wall thicknesses greater than 5 mm in the esophagus, stomach, and colon and 4 mm or greater in the small bowel are considered abnormal. If the thickened wall has a target or double-ringed appearance, it is most likely caused by benign disease. In general, the CT findings of asymmetric or focal wall thickening, nodularity, and thickening greater than 1.5 cm suggest a malignant process. Although it is commonly associated with benign disease, diffuse thickening can also result from some infiltrating malignant diseases. Careful review of CT scans for evidence of metastatic disease and adenopathy and correlation with clinical information aid in the differential diagnosis.