Introduction: In a prospective study the diagnostic validity of magnetic resonance mammography (MRM) as well as its impact on the choice of the operative procedure in the treatment of breast cancer was examined. In 125 patients who were suspected of having breast cancer by clinical examination, ultrasound, and X-ray mammography, additional bilateral MRM was performed. Of special interest was the diagnostic potential of MRM with regard to multifocal, multicentric and contralateral lesions.
Methods: After a complete resection all lesions diagnosed by the various conventional methods were examined patho-histologically. In 112 patients, complete data were available to calculate the sensitivity and the specificity of each method as well as to correlate its results with the pathohistological findings.
Results: In 91 cases, a breast carcinoma was diagnosed by conventional methods, with a sensitivity/specificity of 73%/67% for clinical examination, of 58%/86% for ultrasound, and of 89%/20% for X-ray mammography. In this preselected series of patients with a prevalence of 81.25% the diagnosis established by the various methods was confirmed by MRM with sensitivity of 96.7% and specificity of 19%. Forty-six additional suspicious lesions were found only by MRM, of which 28 were malignant (25 multifocal or multicentric and 3 contralateral carcinomas), and 18 benign. The rate of false-positive MRM results was 18%. Due to the MRM findings, the therapeutic procedure was changed from breast preservation to mastectomy in 14.3%.
Conclusion: Not only for the differential diagnosis of discrepant findings between X-ray mammography and ultrasound, but especially for the diagnosis of multifocal or multicentric lesions, MRM seems to be the method of choice. Consequently, MRM plays an important role in planning the operative procedure in breast cancer patients, especially in the context of breast preservation. To ensure optimal use of this new diagnostic tool high technical standards, proper expertise on the part of the examining radiologist, and effective cooperation among the involved disciplines (radiology, pathology, surgery) must be guaranteed.