IN-VITRO MR-IMAGING OF THE RESECTED STOMACH WITH A 4.7-T SUPERCONDUCTING MAGNET

PURPOSE: To study the effects of formalin fixation, signal intensity c haracteristics of the stomach-wall layers, and findings suggestive of cancerous invasion to the stomach wall in vitro with magnetic resonanc e (MR) imaging in humans. MATERIALS AND METHODS: MR images of nine spe cimens of stomach cancer and 29 normal specimens were obtained at 4.7 T; 26 of the normal specimens were fixed in 10% formalin for 2 hours t o 187 days before imaging. The field gradient was 10 G/cm; the spatial resolution, 0.1 mm. RESULTS: The mucosal, submucosal, and proper-musc le layers were clearly identifiable. The submucosa of the fresh specim ens had the lowest signal intensity of all specimens on both T1- and T 2-weighted images (P < .01). No statistical correlation existed betwee n signal intensity and duration of fixation. Tumor invasion was detect ed in seven of eight specimens with mucosal invasion, all eight specim ens with submucosal invasion, and three of six specimens with muscle i nvasion. CONCLUSION: In vitro MR imaging enabled differentiation of al l three layers of the stomach wall, detection of the cancer, and measu rement of the depth of invasion.