Diffusion-Weighted MRI for Breast Cancer Screening in Women With a Personal History of Breast Cancer

* Primary objective: to compare the screening performance of DW MRI versus mammography alone or combined mammography and ultrasonography in women with PHBC. * Secondary objective: to compare the tumor and patient characteristics detected by DW MRI and combined mammography and ultrasonography in women with PHBC. * This is a prospective, single center, observational cohort study. * A total of 1694 women will be enrolled in this study. * Two latest 3.0 T MRI scanners with dedicated 16- or 18-channel bilateral breast coil are used for DW MRI. For DW MRI screening, the high-resolution echo-planar imaging sequence is designed to have an in-plane resolution of 1.3 x 1.3 mm and a slice thickness of 3 mm. Three b values of 0, 800, and 1200 sec/mm2 are used and ADC maps are generated based on the b=0 and 800 sec/mm2 DW MRI data. The DW MRI images are reconstructed into single summation images with maximum-intensity projections (MIPs) in the sagittal and axial planes. In addition, T1-weighted imaging sequence is also obtained with in-plane resolution of 1.0 x 1.0 mm and a slice thickness of 1 mm. * All patients with PHBC undergo digital two-dimensional mammography and physician-performed whole-breast ultrasonography on the same day. DW MRI and conventional imaging (mammography and ultrasonography) are alternatively scheduled at 6-month intervals and the order has been randomized. * Mammography alone, combined mammography and ultrasonography, and DW MRI will be interpreted independently according to the Breast Imaging Reporting and Data System (BI-RADS) and likelihood of malignancy (Score range, 0%-100%) by trained radiologists. DW MRI interpretation guidelines to be used in this study are based on both qualitative and quantitative assessments. Radiologists are required to successfully complete a training case series of 100 DW MR studies prior to interpreting the DW MRI. * A negative examination result is defined as a final assessment BI-RADS category of 1, 2, 3 and a positive examination result is defined as a final assessment BI-RADS category of 4 or 5. * Biopsies of DW MRI-detected lesions are performed under ultrasonography guidance whenever possible or with MR guidance if there is no correlative ultrasonography finding. Pathology of core or surgical biopsy and 1 year follow up is the reference standard.