[Magnetic tomography of the breast].

Magnetic resonance imaging (MRI) is emerging as one of the most promising, but controversial areas in breast imaging. In recent years interest has been shown in the method because of improved MRI technology and the use of gadolinium-based contrast media for lesion enhancement. Dynamic contrast medium-enhanced MRI has a sensitivity of more than 96% for the detection of breast cancer, because the breast cancer image is enhanced after intravenous administration of gadolinium. MRI seems to be more accurate than other imaging modalities for measuring the size of the cancer, and for detecting multicentric disease and residual tumours. However, many benign lesions show an enhanced image where intravenous gadolinium is used, so that the specificity of MRI has been relatively poor in most studies. Careful assessment of lesion morphology and quantitative enhancement characteristics may help to differentiate benign tumours from malignant lesions, thus increasing specificity. The exact role that breast MR imaging will play in the diagnosis of breast abnormalities has yet to be defined. Mammography and ultrasonography remain the basic imaging modalities for evaluating breast cancer. MR examination is costly, and the appropriate use of MR imaging resources will require careful integration of this new technology with existing strategies for diagnosing breast conditions.