Breast BIRADS grading: (Breast imaging reporting and data system) grading is the standard adopted in the “Breast imaging reporting and data system” created and recommended by the American College of Radiology (ACR) in 1992 to indicate breast changes. It has been revised three times since then, and by 2003, it not only guides the diagnosis of mammography (4th edition), but also adds ultrasound and MRI. The standardization of diagnostic reports for all imaging normal and abnormal conditions of the breast as a whole organ, the use of uniform terminology, standard diagnostic categorization and examination procedures, allows radiologists to have rules to follow in their diagnosis, and also strengthens the coordination and tacit understanding between radiology and other relevant clinical departments, so that clinical treating physicians know what to do next once they read the radiologist’s report. 0 The imaging assessment is incomplete and requires further evaluation. It is recommended to combine with clinical examination, or other imaging examinations. I Negative Follow-up is recommended. II Consider benign changes Recommend regular follow-up (e.g., once a year). III Benign disease possible (about 2% malignant possible). However, a shorter follow-up period (e.g., once every 3 to 6 months) is required, and the percentage of malignancy at this level is less than 2%. IV A Low grade can be malignant Recommend puncture biopsy, with benign results suggesting follow-up. B Moderate suspicion of malignancy Recommend puncture biopsy, with excision if papilloma. C Moderate concern (atypical signs of malignancy) Recommend biopsy, pathologists should be cautious about taking such tissue, with short-term follow-up if benign. V Highly suspicious of malignant lesions (greater than or equal to 95% considered malignant disease). Surgical excisional biopsy and appropriate management are required. VI Biopsy with pathological confirmation of malignant lesion. Surgical excision. Category 1 Mammography shows clear mammary structures without lesions. Note that what is often used in our country as so-called cystic hyperplasia, lobular hyperplasia, and adenopathy (collectively referred to as fibrocystic changes or dysplasia) are all classified in this category according to the BI-RADS description. If a lump is clinically detected with limited asymmetric changes, it cannot be classified in this category despite the final diagnosis of sclerosing adenopathy and may be classified in category 3 or 4A. Intramammary lymph nodes and anterior axillary lymph nodes showing a hypodense lymph node gate (lateral view) or a central hypodensity (axial view of the lymph node gate) are considered normal lymph nodes and belong to category 1. Category 2 Definite benign breast masses (e.g. fibroadenoma, fibrolipid adenoma, lipoma, simple cyst, cumulus cyst, cumulus oil cyst) and definite benign calcifications (e.g. circumferential calcifications, short strips of calcifications with clear borders, coarse speckled calcifications, sparse and single sized dotted calcifications, crescent-shaped sedimentary calcifications, etc.) belong to this category. However, clear margins of the mass are not a necessary condition to exclude malignant lesions, and in women older than 35 years of age, attention should be paid to the search and recall of old films for comparison, or follow-up to observe changes, and therefore may be evaluated as category 0 or 3, respectively. Category 3 BI-RADS classification 2-3 identification BI-RADS classification 4-5 identification (probably benign) is reserved, and its findings are almost certainly benign. It must be emphasized that this category is not an indeterminate type, but for mammography it has a less than 2% chance of being malignant (i.e. almost always benign). The presentation is gradually recognized, based on images with or without previous screening results. Evaluation with additional projections and/or ultrasound of the breast in other orientations requires a category 3 (probably benign). This type of lesion includes well-defined masses that are not visualized on conventional radiographs (unless they are cysts, intramammary lymph nodes, or other benign lesions), limited asymmetric changes with thin sections on spot compression films, and fine punctate clusters of calcifications. Short-term follow-up was performed using unilateral radiographs 6 months after routine mammographic findings. Category 3 may be immediately biopsied for reasons such as clinician or patient fear of tumor and reluctance to follow up, and in these cases the final diagnostic evaluation classification should be based on the risk of malignancy rather than on the management offered. Lesions that are judged by ultrasound as possibly benign include complex cysts that cannot be palpated. The malignancy rate of non-palpable ovoid hypoechoic nodules that cannot be distinguished from complex cysts has been reported to be less than 2%. Clusters of microcysts without discrete solid components may also be rated as category 3. Proper classification of category 3 requires review of the physician’s practice. The malignancy rate in such cases should be less than 2%. For ultrasound, the malignancy rate should also be less than 2%, but this has not been confirmed in a wide range of articles. For MRI, cases classified in this category have only been followed up for a short period of time and their malignancy rate needs further study. Category 4 BI-RADS Classification 4-5 Identification BI-RADS Classification 2-3 Identification Used to indicate interventional radiology procedures that require biopsy from complex cyst aspiration to polymorphic calcification. Many units subclassify category 4 to account for differences in interventional management and risk of malignancy. This uses the receiver-operating characteristic curve (ROC curve) analysis, which is subject to greater clinical scrutiny to help clinicians and radiologists. 4 categories are divided into three subcategories to help achieve these purposes. Category 4A: This is used to represent lesions that require interventional management but are less malignant. Their pathology is not expected to be malignant, and routine follow-up for 6 months after benign biopsy or cytology findings is appropriate. This category includes some solid masses with palpable, partially well-defined margins, such as ultrasound suggestive of fibroadenoma, palpable complex cysts, or suspicious abscesses. Category 4B: Includes lesions with moderate suspicion of malignancy (intermediate suspicion of malignancy). The correlation between radiological diagnosis and pathological findings is close to agreement. In this scenario, benign follow-up depends on this concordance. A partially well-defined, partially indistinct mass that may be a fibroadenoma or fatty necrosis is acceptable; however, papilloma requires excisional biopsy. Category 4C: This category represents lesions of moderate to strong malignancy (moderate concern) that do not yet have the typical malignant features of category 5. This category includes, for example, solid masses with poorly defined borders, irregular shape, or new microscopic polymorphic clusters of calcifications. Such pathologic findings are often malignant. These subcategories of category 4 should encourage pathologists to proceed with further analysis of lesions reported as benign in category 4C, and clinicians should be made aware of the need for follow-up review of cases diagnosed in category 4 but reported as benign on biopsy. Category 5 is used to express lesions that are almost certainly breast cancer. In earlier versions of BI-RADS, when puncture biopsy to obtain a histologic or cytologic diagnosis was not yet widely available, category 5 predicted that the lesion would eventually be disposed of without a prior tissue specimen. Now, specimens with such findings must be retained to detect typical breast cancers with a 95% probability of malignancy. Irregularly shaped masses with burrs, thin strips of calcifications in a segmental or linear pattern, or irregularly shaped masses with burrs and accompanying irregular and polymorphic calcifications are classified as category 5. Normative biopsies without typical malignant lesions are classified as category 4. Category 6 is a new category added to describe cases with biopsy-confirmed breast cancer but with only limited prior treatment (e.g., surgical excision, radiation, chemotherapy, or mastectomy). Unlike BI-RADS categories 4 and 5, category 6 does not require intervention to determine if the lesion is malignant. A second diagnosis found in a previous specimen and shown to be malignant, or testing the effects of neoadjuvant chemotherapy administered prior to surgery can be assessed as category 6.