Purpose: Abbreviated Breast MRI (AB-MR) is a recently introduced protocol for screening in high risk women. The protocol consists of only one pre- and one postcontrast acquisition and their derived images: first postcontrast subtracted sequence (FAST) and maximum-intensity projection (MIP) images, which are acquired in approximately 3 minutes. Using such a protocol, interpretation of screening MRI becomes a dichotomized process of either "normal" (return for routine screening in 1 year) or "further evaluation needed" – recall patient. The purpose of this study was to evaluate the estimated recall rate of screening MRI using AB-MR in a cohort of BRCA mutation carriers in first and second round screening.
Patients and Methods: Retrospective evaluation of screening breast MRI examinations in 50 consecutive healthy BRCA mutation carriers was performed. From these MRI examinations, only the first FAST and MIP images were extracted, simulating an AB-MR examination. Images were initially reviewed with no comparison to prior examinations, simulating first round screening and then evaluated with 1 prior comparison MRI (1-3 years; first FAST and MIP only) to simulate second round screening. Each examination was assigned an interpretation of either "normal" or "recall patient for further evaluation". Patients with prior history of breast surgery were excluded.
Results: Mean age was 48 years (29-68 yrs). Breast density was equally fatty and dense in the study cohort (50% each). BPE was predominantly mild to moderate (grade 1 or 2) with only 18% showing significant BPE. On the simulated first round screening recall was requested in 25/50 patients (50%), reducing to 11/50 (20%) on simulated second round screening. FAST detected all lesions initiating recall whereas 5/25 (20%) were obscured on MIP images. Lesions resulting in a recall were masses in 56% (ave size 0.6 cm) and Non Mass Enhancement in 44% (ave size 1.7 cm). All lesions initiating a recall in this cohort were benign on biopsy or long term follow-up.
Conclusion: If AB-MR is implemented, a significantly high initial first round screening recall rate of 50% can be expected, dropping to 20% on second round screening.
