[Plain MR imaging of breast lesions: a study using 3 mm slice thickness]

MR images of 66 patients with palpable breast masses were reviewed. The histological diagnoses were 46 carcinomas and 20 benign lesions. T1- and T2-weighted sagittal images were obtained with a 3 mm slice thickness, 15 cm field of view and 256 x 192 matrix using a 10 cm receiver coil in a 1.5 Tesla system. Thirty-three carcinomas and 12 benign masses were detected on T1-weighted images. Thirty-five carcinomas and 12 benign lesions were detected on T2-weighted images. Thirty-nine carcinomas and 14 benign lesions were detected on T 1- and/or T2-weighted images. High signal areas on T2-weighted images were found in 22 carcinomas and 5 benign lesions. Low signal areas on T2-weighted images were found in 12 carcinomas and 5 benign lesions. Fine spicules were found on T1-weighted images around 13 carcinomas, but were not found around any benign lesions. This result suggested that the fine spicules might be the only useful finding to differentiate malignancy on MR images without contrast medium.