Unenhanced Magnetic Resonance Imaging In The Evaluation Of High Risk Breast Cancer Individuals

e12579 Background: Individuals at high risk of developing breast cancer benefit from an annual surveillance with contrast enhanced breast magnetic resonance imaging (CEMRI). However, this technique has high rate of false positive findings and is associated with complications related to contrast media administration. Diffusion Weighted Imaging (DWI) is a fast sequence that does not need contrast media. Methods: We retrospectively reviewed 198 breast MRI performed to individuals that are under surveillance at the High Risk Clinic. 42 were BRCA 1 mutation carriers ,45 BRCA 2 and 111 belonging to non-informative BRCA1/2 test families. 13 patients (7 BRCA 1, 2 BRCA 2 and 4 non informative) developed breast tumors. CEMRI and DWI was analyzed. We considered as suspicious of malignancy a lesion with Apparent Diffusion coefficient (ADC) equal or less than 1x10-3 mm2 xsec-1 . Samples were obtained when CEMRI indicated suspicion of malignancy. This analysis was performed by two radiologists. Results: Thirteen malignant lesions were found in our study. Two neoplasms were only detected in DWI and not in CEMRI. The first reader detected neoplasm in all cases using DWI . Sensibility, specificity, positive predictive value and negative predictive value for CEMRI were 81%, 33%, 53% and 67%. For DWI were 100% , 94,59%, 56,52% and 100%. DWI values obtained by the second reader were 53,85%, 79,46%, 15,56% and 96,08%. The concordance observed between both readers was 0,23 (K) IC 95%(0,078-0,3920). In 2012 MRI equipment was improved. When studying the DWI values after this year, the first reader achieved 100%, 95,28%, 37,5% and 100% (sensibility, specificity, positive predictive value and negative predictive value) and the second reader 66,67%, 80,19%, 8,7% and 98,84%. Conclusions: Our results showed that DWI seems to be more accurate to predict malignant lesions in patients at high risk of breast cancer. However there was an important inter-observer variability, which can be improved with better acquisition technique. Further prospective studies should determine the predictive value of DWI with respect to CEMRI in the annual surveillance of High Risk individuals.