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 miR-21 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 miR-21 can significantly improve the diagnostic efficacy of breast lesions.