[CT diagnosis of the gastrointestinal tract]

Five topics regarding CT diagnosis of the gastrointestinal tract are discussed with illustrative cases: 1) Fat-containing tumors can be seen in the esophageal lumen, and their differential diagnosis includes not only lipoma and liposarcoma (sometimes teratoma) but also fibrovascular polyp and carcinosarcoma. 2) The multi-layered pattern of the gastric wall observed on dynamic CT is important for the differential diagnosis of gastric lesions and the staging of gastric cancer. 3) Swelling of the sentinel lymph nodes is an important finding for correct staging of cancer, incidental detection of occult cancer, and diagnosis of the origin of abdominal tumors. 4) Air-inflated CT and virtual CT endoscopy of the colon are necessary for the detection of small colorectal cancers, and multi-planar reconstruction (MPR) images vertical to the lesions are helpful for cancer staging. 5) MRI and CT with MPR images are useful for the evaluation of anorectal fistula.