Breast aspect ratio should refer to the aspect ratio of the breast nodule during the ultrasound examination, and a breast nodule with an aspect ratio greater than 1 is likely to be benign. A breast nodule with an aspect ratio greater than 1 is a sign of malignancy, but it is not possible to make a definitive diagnosis on this point alone. Clinical observation of other features of the breast nodule is usually continued to make a diagnosis of the nature of the breast nodule, which mainly includes the margin of the nodule, calcification inside the nodule, and blood circulation inside the nodule. 1. Nodal margins: nodules with clear margins are benign; nodules with blurred margins and burr-like changes are usually malignant. 2. Internal calcification of the nodule: internal calcification can reflect the malignant possibility of the nodule; obvious clusters and gravel-like calcification within the nodule are more likely to be malignant. Benign breast nodules usually have no obvious calcification. 3. Internal blood circulation of the nodule: Usually, malignant breast nodules have obvious internal blood circulation; benign nodules usually have poor internal blood circulation. The above features, together with the aspect ratio of the breast nodule, are important factors in determining the nature of the nodule on imaging, but the evidence for determining the nature of the nodule on the basis of a single factor is insufficient. Therefore, a breast nodule with an aspect ratio greater than one is not necessarily malignant, but may be benign, and the patient needs to undergo further examination to clarify the nature of the nodule.