MR Imaging of Gastric Carcinoma

Magnetic Resonance (MR) imaging has not become popular for staging of gastric carcinoma because of a number of limitations, including motion artifacts, lack of a stable contrast medium, and the high cost. However, continuous technical improvements have been made in MR imaging of the abdomen, thereby reducing motion artifacts and improving image quality. These improvements include breath-hold fast imaging techniques, placement of abdominal binders, administration of antiperistaltic agents, and the use of phased array coils. In vitro studies using 1 4.7T MR systems have shown that MRI allows the depiction of gastric wall layers and therefore, technically permits the evaluation of the local tumor stage of gastric carcinomas. However, MR study in gastric carcinoma is challenging and it has much possibility. Usually, the preoperative staging workup of gastric carcinoma is performed mainly with computed tomography (CT). CT has been a favored method for preoperative evaluation and staging in patients with gastric carcinoma (Goldberg & Thoeni. 1989; Werthmuller & Margulis. 1991; Halvorsen & Thompson. 1991). Parallel advances in CT equipment and scanning techniques have reduced scanning time and decreased motion artifacts. Simultaneously, rapid IV contrast administration with an automatic power injector has improved contrast enhancement of the gastric wall and gastric carcinoma. Helical CT has advantages over conventional CT, including faster scanning time and fewer respiratory misregistration artifacts in a single breath-hold (Hahn, et al., as cited in Stark & Bradley. 1992). However, CT is limited, particularly in the diagnosis of lymph node metastasis, peritoneal metastasis, and small hematogenous metastasis. Endoscopic sonography has been reported to be the most accurate technique for the T staging of gastric carcinoma because it can define five layers of the gastric wall (Botet, et al. 1991). But this technique cannot evaluate other factors such as liver metastasis and peritoneal seeding. In addition, endoscopic sonography is an invasive technique dependent on the operator.