Objective: To explore the potential association between the multimodal ultrasound characteristics and pathological classification of BI-RADS category 4 breast lesions, so as to clarify the diagnostic characteristics of multimodal ultrasound in different pathological types BI-RADS category 4 breast lesions.

Materials and methods: Patients who visited in The First Affiliated Hospital of Shandong First Medical University ＆ Shandong Provincial Qianfoshan Hospital were collected. Their general clinical features, information on preoperative ultrasound diagnosis, and postoperative pathologic data were reviewed.

Inclusion Criteria:

• Perform ultrasound examination at our hospital before surgery or puncture biopsy; Complete histopathological data; Two ultrasound physicians with more than 5 years of experience in breast ultrasound diagnosis were diagnosed as BI-RADS Class 4 based on preoperative ultrasound images.

Exclusion Criteria:

• Poor image quality; Incomplete clinical data.

Patients who visited in The First Affiliated Hospital of Shandong First Medical University ＆ Shandong Provincial Qianfoshan Hospital were collected.