Preoperative MRI of pure intraductal breast carcinoma--a valuable adjunct to mammography in assessing cancer extent.

The aim of the study was to evaluate the contribution of preoperative breast magnetic resonance imaging (MRM) as an adjunct to mammography in assessing extent of pure ductal carcinoma in situ (DCIS) and to relate magnetic resonance imaging (MRI) findings to histopathological features. A retrospective analysis was conducted of 86 histologically proven cases of pure DCIS of the breast. Two experienced radiologists with knowledge of clinical and histopathological findings at the time of the review evaluated mammographic and preoperative MRI results by consensus. Compared to histopathology, mammography or MRM alone underestimated DCIS extent in 18.6% and 31.4% of cases, respectively. When both imaging modalities were considered, DCIS extent was underestimated in 8% of cases. Combined use of mammography and MRM revealed good agreement with histopathology to assess DCIS extent (kappa=0.439; P<0.001). MR enhancement of DCIS was related to histologic size (P=0.011). Mammography is more accurate than MRM in assessing cancer extent of pure DCIS, but combined use of both imaging techniques leads to improved accuracy.