Diagnosis and staging of gastric cancer.

The biphasic upper gastrointestinal examination using barium and gas distention of the stomach is approximately as accurate as endoscopy in the detection of gastric cancer. Endoscopy allows biopsy of suspicious lesions but is more invasive and costly. The barium examination can reliably differentiate gastric ulcers into three categories: benign, malignant, and equivocal. The radiographic findings in gastric carcinoma are described in detail. Staging of gastric cancer is limited by the inability of imaging techniques such as computed tomography (CT) or magnetic resonance imaging (MRI) to detect tumor in normal size lymph nodes. Determination of the presence or absence of local invasion is also difficult in many cases. CT and MRI are effective but imperfect tools for the detection of liver metastasis. Technique and pitfalls in the use of CT and MR in staging gastric carcinoma are emphasized.