I am often asked what BI-RADS means in a mammogram or ultrasound report. In fact, it is the abbreviation of Breast Imaging Reporting and Data System, which is a system recommended by the American College of Radiology to make mammogram, ultrasound and MRI reports more uniform. There are seven levels. The meaning of each grade is as follows: Grade 0: Needs to be recalled and reevaluated in conjunction with other exams. It means that the information obtained from the examination may not be complete. Grade I: No abnormality is seen. Grade II: benign changes are considered and regular follow-up is recommended (e.g., once a year). Grade III: Benign disease is possible, but a shorter follow-up period (e.g., once every 3-6 months) is required. The percentage of malignancy at this level is less than 2%. Grade IV: Malignant lesion is considered possible and requires biopsy for clarification. Grade V: High suspicion of malignant lesion (almost identified as malignant disease), requiring surgical excisional biopsy. Grade VI: Malignant lesion has been confirmed by pathology. Of course, the above grading is only to determine the degree of breast disease from the images, the specific situation should be combined with the clinician’s judgment to comprehensive analysis.