[Normal wall thickness and neoplastic wall changes in the gastrointestinal tract as shown by computed tomography]

55 patients with tumours of the gastrointestinal tract were examined by CT, using a paraffin emulsion as a negative oral contrast medium. These were compared with 119 normal patients. The appearance of normal and tumour bearing portions of the gut wall against the contrast medium was studied. Under hypotonic conditions the gut wall could regularly be distinguished from surrounding organs and gut content. Mural thickness of the oesophagus greater than 7 mm and of the stomach and colon greater than 8 mm must be regarded as abnormal. Benign diseases cannot be distinguished from malignant conditions on the basis of wall thickness. Artifacts, such as are caused by positive oral contrast, were of less significance when using paraffin emulsion.