[Enhanced MRI of breast cancer smaller than 3 cm]

Twenty-two patients with breast cancers were studied using magnetic resonance (MR) imaging with a cylindrical surface coil at 1.5 Tesla. All were examined with the FE sequence and Gd-DTPA as a contrast medium. These images were compared with micrographs of the specimens. All cancers were enhanced clearly, and demarcated margins or spiculations of the tumors were seen as clearly on MR images as on micrographs of the specimens. In 12 patients (9 carcinomas, 2 fibroadenomas and 1 benign phyllodes tumor), dynamic studies were performed after the intravenous injection of Gd-DTPA. All nine carcinomas showed enhancement characterized by a sudden increase in signal intensity on the order of 100% or more within the first 2 minutes after injection. Two fibroadenomas were enhanced slowly. Thirteen patients with breast cancers were examined with several sequences (FE, T1-weighed SE, T2-weighed SE and STIR) with or without Gd-DTPA. The most clearly delineated images of the tumors were those of FE images with Gd-DTPA enhancement. A phantom constituted of various concentrations of Gd-DTPA in 20% albumin solution was measured by signal intensities with T1-weighted SE sequence and FE sequence. The ratio of enhancement of the 20% albumin solution relative to the Gd-DTPA concentration was higher with the FE sequence than with the SE sequence. The sensitivity of the FE sequence to Gd-DTPA enhancement was 1.5 times that of the SE sequence under the usual concentration of Gd-DTPA.