MR imaging-detected breast lesions:: Histopathologic correlation of lesion characteristics and signal intensity data

OBJECTIVE. The aim of our study was to differentiate benign from malignant breast lesions that had been detected exclusively on MR imaging by analyzing qualitative and quantitative lesion characteristics. MATERIALS AND METHODS. We performed 51 MR imaging-guided breast interventions (41 preoperative lesion localizations and 10 large-core needle biopsies) in 45 patients with exclusively MR imaging-detected lesions. All patients had previously undergone diagnostic dynamic contrast-enhanced MR imaging of the breast with a double breast coil 1.0 T (n = 36) or 1.5 T (n = 15). The diagnostic MR images were evaluated on a workstation. Lesion morphology (size, shape, margin type, enhancement pattern), signal intensity (time to peak enhancement, maximum slope of enhancement curve, washout, relative water tent), and scores analogous to the Breast Imaging Reporting and Data System (BI-RADS) categories were correlated with histology. RESULTS. Histology revealed malignancy in 37.3% (19/51) of the lesions. The predictive value for malignancy of exclusively MR imaging-detectable lesions increased the analogous BI-RADS category increased. Late inhomogeneous contrast enhancement the only morphologic criterion that was statistically significantly correlated with malignancy. Malignant and benign lesions did not differ significantly in any of the quantitatively signal intensity parameters. Carcinomas showed a tendency toward faster and stronger enhancement and stronger washout. CONCLUSION. The classification of exclusively MR imaging-detectable breast according to a combination of morphologic and pet-fusion parameters including the late enhancement pattern helps identify the lesions for which interventional MR imaging is Quantitative signal intensity data alone do not suffice.