[Gastric adenocarcinoma: magnetic resonance versus surgical staging]

Preoperative MR staging in 34 patients with gastric adenocarcinoma was compared with postoperative histologic findings to evaluate MR sensitivity, specificity and accuracy. MR exams were carried out with an 0.5-T superconductive magnet, with SE T1- and T2-weighted sequences on axial and sagittal planes, 10-mm slice thickness and 3-mm interval. The stomach was distended with a watery solution of Gd-DTPA. MRI showed the tumors only in their advanced stage. MR sensitivity was high in detecting hepatic metastases, but peritoneal carcinomatosis was difficult to demonstrate because of inherent technical MR limitations, such as motion and respiratory artifacts. MRI had 40.6% sensitivity, 93.87% specificity and 42.08% accuracy in demonstrating lymph node involvement. Hepatoduodenal lymph nodes were particularly difficult to study, as were those in the splenic hilum and artery. No correlation was found between tumor invasion and lymph node size. MRI exhibits many limitations in gastric carcinoma staging because of motion and respiratory artifacts and of the long acquisition times needed for gastric studies. However, MR sensitivity and specificity are similar to those of CT, as reported in the literature.