Measurement of the vascular index for the superb microvascular imaging (SMI) of a 40-year-old woman with fibroadenoma.When a Doppler image or video file in Digital Imaging and Communications in Medicine format is opened in the dedicated software and the region of interest (ROI) is set as the entire target lesion (yellow line), the vascular index (red box) is automatically calculated. The vascular index is the ratio between the pixels for the Doppler signal and those for the total lesion. This SMI shows a Breast Imaging Reporting and Data System category 4A mass with a few branching or penetrating vessels and a vascular index of 13.9%. Biopsy revealed fibroadenoma.