Staging of esophageal carcinoma in vitro with 4.7-T MR imaging

PURPOSE: To determine the accuracy of 4.7-T magnetic resonance (MR) imaging for evaluating the mural invasion of esophageal carcinoma. MATERIALS AND METHODS: Sixty-seven esophageal specimens containing 70 squamous cell carcinomas were studied with a 4.7-T MR system with a 4-cm-diameter surface coil. Spin-echo MR images were obtained with a field of view of 4-6 cm, matrix size of 256 x 256, and section thickness of 3 mm, which resulted in a voxel size of 0.08-0.16 mm(3). MR findings were compared with histopathologic findings, which served as the standard of reference. Tumor invasion on MR images was determined by consensus of two radiologists. RESULTS: T2-weighted images depicted six to eight layers of the normal esophageal wall; these correlated well with layers identified with histologic examination. In 66 (94%) of 70 cases of esophageal carcinoma, the depth of mural invasion visualized with MR imaging correlated well with that determined with histopathologic examination. The stage determined with MR imaging, however, was higher in two (3%) and lower in two (3%) cases than that determined with histopathologic examination. MR imaging enabled visualization of the gross features of tumor growth pattern, tumor ulceration, and adjacent lymph node involvement. CONCLUSION: MR imaging in vitro allows accurate assessment of the mural invasion of esophageal carcinoma and thus potentially enables preoperative histopathologic staging.