Purpose: Contrast enhanced MRI of the breast provides high sensitivity but variable specificity in detecting breast cancer, and may lead to excessive benign biopsies. Based on previous success with the application of delayed contrast MRI (DCM) in differentiating tumor/non-tumoral regions in brain tumor patients, we aim to study the feasibility of applying DCM to breast cancer patients in order to potentially reduce the number of benign unnecessary biopsies.
Materials and Methods: Fifty two women undergoing breast MRI were randomly recruited and scanned by standard DCE-MRI, acquired up to 5 min post contrast, as well as with DCM acquired 20 minutes post contrast. Of them twenty five women`s MRI score was BIRADS4 and they were biopsied. Image analysis was provided via in-house developed software, affording color coded maps reflecting contrast accumulation/clearance (depicted red/blue in the maps) at the delayed time point. DCM maps were retrospectively compared with the results of the conventionally obtained diagnostic workup.
Results: A total of 69 lesions were evaluated. All 19 malignant and high risk lesions (IDC, DCIS, papillary lesions) correctly appeared blue in the DCM maps while 42 of the benign lesions appeared red. Another eight lesions appeared mixed or blue. No false negative cases were obtained. False positive cases (blue for benign) were mainly due to hemangiomas, fat necrosis and fibroadenomas with myxoid components. Standard DCE resulted in 100%/52%/44%/100% sensitivity/specificity/PPV/NPV to breast cancer, while DCM resulted in 100%/84%/70%/100%, respectively. Further comparison of DCM maps with histology specimens suggested that high vessel density with vessel compression appeared blue in the maps (contrast clearance at 20 min) while low vessel density with dilated lumens appeared red (contrast accumulation).
Conclusion: DCM may provide improved specificity for diagnosis of breast cancer. Further application, aimed in optimization of biopsy planning is now underway.
