BIRADS 3 MRI lesions: Was the initial score appropriate and what is the value of the blooming sign as an additional parameter to better characterize these lesions?

•Blooming sign is lower in benign lesions (3.03%) than in malignant lesions (17.9%).•The malignancy rate in ACR3 lesions was <2% even in high-risk population.•Blooming sign increased MRI performance and may reduce unnecessary biopsy.

ObjectiveTo investigate whether there were suspicious criteria on the initial MRI in BIRADS 3 lesions.To analyze the value of “blooming sign” as an additional criterion for malignancy.Materials and methodsIn this retrospective study the lesion morphological and enhancement characteristics were analyzed.The “blooming sign” (BS), defined as the lesion size increase between the early and the late phase after gadolinium was assessed.We determined the optimal cut-off value for the BS to distinguish benign and malignant breast lesions.Results100 lesions were classified BIRADS 3 in 75 patients (12%).Four of the five malignant lesions had suspicious BIRADS criteria on the index MRI.45 lesions were stable and 30 lesions resolved spontaneously during the follow-up MRI.The optimal cut-off value for the BS was 8.54% with 100% sensitivity, 94% specificity, 44% positive and 100% negative predictive values.Using reclassification rule to upgrade benign BIRADS lesions with suspicious BS feature and downgrade suspicious BIRADS lesions with benign BS feature increased MRI specificity (89%), sensitivity (100%) while preserving NPV (100%).ConclusionsThis study showed the suggestive part of classified BIRADS 3 lesions. The blooming sign seems to be a good additional parameter to increase MRI specificity when associated to BIRADS criteria.