Improved accuracy in differentiating malignant from benign mammographic abnormalities: a simple, improved magnetic resonance imaging method.

BACKGROUND

Although several refinements have been reported for breast magnetic resonance imaging (MRI), there has been no uniform agreement by researchers on the optimal method. The authors report a simple and effective MRI method that incorporated the best qualities of other breast MRI methods yet eliminated the complexity of dynamic sequences and computer subtraction. This new method used fat-suppression, a 3D technique, a dedicated breast coil, and quantitation of lesion enhancement.

METHODS

Sixty-one mammographically suspicious lesions were evaluated with a fat-suppressed T1-weighted 3D FLASH sequence before and after administration of Gd-DTPA. Abnormalities were evaluated primarily by the degree of lesional enhancement; lesional morphology was assessed as a secondary criterion. For small or multiple lesions, the authors reformatted images to produce MRI findings that corresponded to the mammographic abnormality. To allow accurate pathologic correlation, all subjects underwent stereotactic or excisional biopsy of the suspicious lesions.

RESULTS

Using this new method, all 15 breast carcinomas were enhanced with a signal intensity (SI) increase of > or = 180% (mean = 337%). No benign lesions enhanced at a SI of > 180%. The difference in degree of enhancement between malignant and benign lesions was statistically significant (P < 0.05). There were overlapping degrees of postcontrast enhancement among fibroadenomas (n = 13; mean SI = 70%) and atypical hyperplasias (n =; 11; mean SI = 82%), but morphologic characteristics allowed for discrimination between these two entities. In the remaining benign breast disease lesions, there was minimal enhancement.

CONCLUSIONS

3D fat-suppressed sequencing using this new MRI method accurately discriminated between benign and malignant mammographic abnormalities and eliminated the time-intensive and complex MRI methods without sacrificing accuracy.