Qualitative, quantitative and combination score systems in differential diagnosis of breast lesions by contrast-enhanced ultrasound. 
To assess the feasibility of score systems in differential diagnosis of breast lesions by contrast-enhanced ultrasound (CEUS).  CEUS was performed in 121 patients with 127 breast lesions by Philips iU22 with Sonovue as contrast agent.  Pearson Chi-square χ(2) test, binary logistic regression analysis and Student's t-test are used to identify significant CEUS parameters in differential diagnosis.  Based on these significant CEUS parameters, qualitative, quantitative and combination score systems were built by scoring 1 for benign characteristic and scoring 2 for malignant characteristic.  Receiver operating characteristic (ROC) curve was applied to evaluate the diagnostic efficacy of different analytical methods.  Pathological results showed 41 benign and 86 malignant lesions.  Qualitative analysis and logistic regression analysis showed that there are significant differences in enhancement degree, enhancement order, internal homogeneity, enhancement margin, surrounding vessels and enlargement of diameters (P<0.05) between benign and malignant lesions.  Quantitative analysis indicated that malignant lesions tended to show higher peak intensity (PI), larger area under the curve (AUC) and shorter time to peak (TTP) than benign ones (P<0.05).  Qualitative score systems showed higher diagnostic efficacy than single quantitative CEUS parameters.  The corresponding area under the ROC curve for qualitative, quantitative and combination score systems were 0.897, 0.716 and 0.903 respectively.  Z test showed that area under the ROC curve of quantitative score system was statistically smaller than that of other score systems.  Quantitative score system helps little in improving the diagnostic efficacy of CEUS.  While qualitative score system improves the performance of CEUS greatly in discrimination of benign and malignant breast lesions.  The application of qualitative could develop the diagnostic performance of CEUS which is clinically promising.