Abstract: Objective To evaluate the value of conventional ultrasonography(US),contrast-enhanced ultrasound(CEUS)and their combined application in the diagnosis of small breast carcinoma.Methods A total of 85 small breast neoplasms(≤2 cm)were prospectively examined with US and CEUS,respectively.The results of imaging classifications were compared with those of pathological diagnosis.The receiver operating characteristic(ROC)curve generated by the method of score was used to evaluate the value of US,CEUS and their combination for small breast neoplasms.Results There were 49 cases of malignant tissue(57.65%)and 36 cases of benign tissue(42.35%)in the 85 cases of breast lesions after surgical removal.Through two groups of three-dimensional chi-square,all the indicators of combined application were superior to the separate use of US and CEUS.The area under ROC curve(AUC)in diagnosis of small breast neoplasm with US,CEUS and their combination were 0.712,0.755,and 0.820,respectively.Results of Z test showed the diagnostic accuracy of combination was superior to the separate use of US(P=0.028)and CEUS(P=0.097).Conclusion US and CEUS are effective methods in the diagnosis of small breast carcinoma and the accuracy can be improved by their combination.