Role of MRI in Characterization of Occult Breast Lesions in High Risk Population

OBJECTIVE:  To evaluate the diagnostic validity of breast MRI in discriminating benign from malignant lesions in women with occult breast lesions who are at a high risk of developing breast cancer, with histopathologic findings and/or follow up used as the reference standard.  PATIENTS AND METHODS: Contrast-enhanced bilateral breast MRI was performed on 100 women at high risk of developing breast cancer with indeterminate imaging findings by mammography and/or ultrasonography. Lesions detected by MRI that could represent potential malignancies in both breasts were evaluated. Morphologic assessment and kinetic analysis (contrast enhancement and time/intensity curves) were performed on each lesion using dedicated postprocessing and display software. Functional MR toolswere used in about 60% of casesto help in the differential diagnosis between malignant and benign of suspicious lesions detected at conventional MRI.  RESULTS: Among 100 patients included in the study12% of the patients were finally diagnosed as free of any pathology, 56% had benign findings, while 31% of the patients were malignant. (24 IDC, 4 Invasive Lobular Carcinoma, 1 Medullary carcinoma, 1 Mucinous carcinoma and 1 DCIS.) The sensitivity, specificity, positive and negative predictive values of CE-MRI, were 100%, 93%, 86%, and 100% respectively. Overall accuracy of MRI breast was 95%. CONCLUSION: Breast MRI is highly effective in detection and characterization of occult breast lesions in high risk population, with excellent sensitivity and high specificity. Development of functional MRI tools contributed to the improving validity of this modality