18 - Gastrointestinal Tumors: Computed Tomography/Endoscopic Ultrasonography

Abstract

In tumors of the gastrointestinal tract, surface morphology, as well as the two-dimensional development of the tumors, is still primarily diagnosed by conventional radiological and endoscopic examinations. At present, the preoperative diagnosis is generally based on the information provided by these two examinations and helps determine the therapeutic strategies that will be employed. With recent technological advances, including virtual endoscopy by three-dimensional CT (multidetector row CT: MD-CT) and three-dimensional ultrasonography (3DEUS), the diagnosis of colonic polyps and three-dimensional images of gastrointestinal tumor lesions has become possible. The depth of tumor invasion and the degree of lymph node metastasis are the most significant prognostic factors in gastrointestinal tumors. The identification and imaging of a lesion by MD-CT are suitable for use in advanced gastric cancer, while 3D ultrasonography is suitable for use in early-stage gastric cancer. Therefore, at present, 3D ultrasonography is used for early gastric cancer and MD-CT for advanced gastric cancer as part of routine examinations in order to precisely measure the 3D structure of the tumor and to determine tumor volume. In patients with a gastrointestinal tumor, an accurate assessment of the local stage of the lesion and the status of metastases in the surrounding area are important for determining an appropriate therapeutic strategy. Currently, gastrointestinal imaging examinations and gastrointestinal endoscopy are done to determine whether a tumor is present and to make a diagnosis Ultrasonography has become useful for diagnosing the depth of tumor invasion.