Mammogram 4a indicates malignancy and further investigations such as breast ultrasound, breast MRI and puncture biopsy are usually recommended. BI-RADS classification is one of the classification criteria commonly used in mammography and ultrasound, and is mainly used for the initial characterization of breast nodules. 4a usually indicates that the breast nodule has a 2% to 9% chance of malignancy, and according to the guideline recommendation, at this point, most of them need to be further improved with other related tests to clarify the diagnosis. Ultrasound is also a common screening test for the breast. For women with dense glands, breast ultrasound is the most commonly used initial screening test, and it can also be used in conjunction with a mammogram to improve the accuracy of the test. Patients are advised to consult a regular hospital and choose the appropriate examination method under the guidance of a doctor.