When reading breast ultrasound reports, we often see this group of letters, many friends in the consultation often mentioned, namely: BI-RADS, this group of letters is the Breast Imaging Reporting and Data System (Breast Imaging Reporting and Data System) of the English acronym, is the current breast ultrasound diagnosis of the general application of the grading evaluation standards. Now let’s take a look at the specific meaning of BI-RADS grading standards: Level 0 (category 0): refers to the use of ultrasound examination can not fully evaluate the lesion, the need for further diagnosis of other imaging tests. For example: 1, there are nipple discharge, asymmetric thickening, skin and nipple changes and other clinical manifestations, and ultrasound has no sign; 2, clinically palpable mass, age greater than 20 years old, ultrasound has suspicious signs or no features, need mammography; 3, ultrasound and mammography have no features, need to identify breast cancer breast-conserving surgery after the formation of scars and recurring foci, the recommended magnetic resonance imaging examination; 4, to determine the treatment of the final evaluator to determine the need for further imaging examination before treatment. Those who need final evaluation before determining the treatment: Category 1: Negative (negative) Refers to the absence of abnormal changes on ultrasonography, which can be confidently judged as normal. Follow-up (one year) is recommended. For example: no mass, no structural disorder, no skin thickening, no microcalcification; Category 2: benign finding/findings Malignancy can be basically excluded. Follow-up (six months to one year) is recommended depending on age and clinical presentation. Examples: Simple cyst Intramammary lymph node (may also be grade 1) Breast prosthesis implantation Fibroadenoma with little change in image on repeated ultrasounds, age less than 40 years, or age less than 25 years on first ultrasound examination; structural irregularity after surgery, but no change in image on repeated ultrasounds. Fatty lobules Grade 3 (category 3): probable benign finding Less than 2% risk of malignancy. Short-term follow-up (three to six months) and other tests are recommended. For example: a solid oval mass with clear borders and an aspect ratio of less than 1, less than 40 years of age, may be benign and the risk of malignancy is less than 2%; fibroadenomas are highly probable: solid masses with oval borders, clear borders, and aspect ratios of less than 1. After two to three consecutive years of follow-up, the original grade 3 (probably benign) may be changed to grade 2 (benign); multiple complex cysts or clusters of small cysts; verrucous growths Nodules (category 4): suspicious abnormality, requires pathology, risk of malignancy 3%-94%. Solid masses with nonbenign ultrasound manifestations (1-2 items). For example: 1. Fibroadenomas and other benign lesions that do not fit all ultrasound images (benign and malignant differential manifestations with nonbenign manifestations (1-3 items); 2. Solid mass lesions with ultrasound benign signs over the age of 40 years, which may not have a characteristic breast cancer pattern but are of a high incidence of age with malignant potential (4A). Subtyping of grade 4: Grade 4A (category 4A): is of low suspicion of malignancy. Pathologic report findings are generally nonmalignant and should be followed up for six months or routinely after a benign biopsy or cytology. Examples include: a palpable, well-defined localized solid mass with ultrasound features suggestive of a fibroadenoma; a palpable complex cyst or possible abscess. Grade 4B (category 4B): lesions with moderate probable malignancy. Lesions falling into this classification have a strong radiologic and pathologic correlation. Partially well-defined and partially ill-defined fibroadenomas or fat necrosis may be followed, but papillomas may require excisional biopsy. Grade 4C (category 4C): malignancy may be greater but does not have the typical malignant appearances as in grade 5. Examples include a poorly defined, irregular, substantial mass or emerging clusters of fine pleomorphic calcifications. Lesions in this category are likely to be malignant in origin. Category 5: High suggestive of malignancy The risk of malignancy is greater than 95%. The risk of malignancy is greater than 95%. There are characteristic abnormalities in the ultrasound (three or more signs of malignancy in the benign and malignant solid mass identification table), and therapeutic measures should be considered. Category 6: known biopsy-proven malignancy This category is used in the imaging evaluation of biopsy-proven malignancy that has not yet been treated. This classification is used for the evaluation of biopsy-proven malignancy that has not yet been treated. It is used to evaluate imaging changes before and after biopsy or to monitor changes in neoadjuvant therapy prior to surgery. The BI-RADS grading criteria were developed as a joint effort of the National Cancer Institute, the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, the American Medical Association, the American College of Surgeons and the American College of Pathologists, and the American College of Radiology. The establishment of the BI-RADS standard has standardized the terminology used to describe the characteristics of breast lesions and the reporting terminology used to evaluate the degree of malignancy of the lesions, and has reduced errors and uncertainties in the interpretation of breast imaging reports, which is particularly important for the review of the diagnosis of breast cancer.