Correlation between diagnostic capability of MR-mammography and histology of tissue adjacent to tumor

The purpose of this paper is to evaluate correlation between the capability in the diagnosis of tumor extent and histology of adjacent tissue. MR-mammography (MRM) was obtained in twenty-one patients with surgically resected breast cancer by 0.5 T superconducting magnet (PHILIPS GY-ROSCAN T5-II, release 3.1). Pre and postcontrast 3D-spoiled gradient echo sequence were employed for MRM with spectral presaturation with inversion recovery (SPIR) and on-resonance MTC. The contrast determination time, the passing time of the center of k-space, was 1 min 50 s in 14 cases with key-hole imaging, and 2 min 46 s in 7 cases without key-hole imaging. Early enhancing area was considered as a tumor and an accuracy of tumor extent was evaluated by two radiologists. Accurate interpretation was obtained in 9 of 9 cases with atrophic mammary gland with fatty replacement and 3 of 3 cases with severe fibrosis in mammary gland. Seven cases were unclear in tumor margin due to intense enhancement of the adjacent tissue. One of 3 cases with normal mammary gland showed unclear margin of the tumor, which corresponded to the area of rich population of lobules in a young patient. Two of 2 cases of fibrocystic change with nonproliferative lesions in one case and proliferative lesions without atypia in another, showed unclear margin of tumor. Two cases of 2 intraductal spreading and 2 of 2 cases of massive interstitial invasion also showed unclear margin. The accuracy of tumor extent was found to have no correlation with either histology or enhancing ratio of the tumor. In conclusion, it is warranted to say that histology of adjacent tissue is an important factor to determine diagnostic capability of tumor extent by MRM. Fat replacement and fibrosis of the surrounding tissue are main causes of clear visualization of tumor, while normal mammary gland in young patients, fibrocystic change, intraductal spreading and invasion lead to the unclearness of tumor margin. (author)