background  Early diagnosis of breast cancer is crucial for its prognosis. Both contrast-enhanced ultrasound and miR-21 levels contribute to the early diagnosis of breast cancer. However, it is unclear whether the combination of miR-21 with conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) can further improve the accuracy of early diagnosis of breast cancer.

Objective To analyze the application value of US and CEUS combined with plasma exosomes miR21 in the diagnosis of breast diseases.

Methods From December 2022 to April 2023, 306 patients (182 benign and 124 malignant) who underwent routine breast ultrasound, CEUS examination, miR-21 test and had clear pathological results in the Department of Ultrasound Diagnosis of Chinese PLA General Hospital were collected prospectively. The diagnostic efficacy of conventional ultrasound, contrast-enhanced ultrasound, and miR-21 in breast lesions was compared and analyzed.

Results The sensitivity, specificity, accuracy and the area under the curve (AUC) of routine ultrasound in the diagnosis of breast cancer were 70.1%, 83.5%, 78.1% and 0.803, respectively; The sensitivity, specificity, accuracy and AUC of conventional ultrasound combined with contrast-enhanced ultrasound in the diagnosis of breast cancer were 81.5%, 87.4%, 85.0% and 0.898 respectively; The sensitivity, specificity, accuracy and AUC of miR-21 combined with conventional ultrasound and contrast-enhanced ultrasound in the diagnosis of breast cancer were 91.1%, 85.7%, 87.9% and 0.948 respectively. The diagnostic efficacy of miR-21 combined with conventional ultrasound and contrast-enhanced ultrasound was significantly higher than that of conventional ultrasound (P ＜0.001) and conventional ultrasound combined with contrast-enhanced ultrasound (P ＜0.001).

Conclusion  The combination of contrast-enhanced ultrasound and plasma exosomes miR21 can significantly improve the diagnostic efficacy of breast lesions.