Clinical Application And Pathological Basic Research Of Ultrasonic Shear Wave Elastography In Breast Lesions

Purposes1. To determine which was the best shear wave elastography (SWE) quantitative parameters of the maximum elasticity (Emax), the mean elasticity (Emean), the minimum elasticity (Emin), the standard deviation (SD) and the ratio of Emean between the lesion and normal tissue (Eratio), and to determine which was the best model of the combinations of the above parameters and Breast Imaging Reporting and Data System (BI-RADS) for ultrasound in assessing benign and malignant breast lesions.2. Evaluate the correlation between stiffness, which was measured by shear wave elastography (SWE), and collagen morphology and arrangement of breast lesions. Explore the pathological basis of stiffness variance of breast lesions.Methods1. In this study,302 breast lesions were performed conventional ultrasound and SWE. Each lesion was classified according to ultrasound (BI-RADS) and pathologic results of all lesions were available. The regions of interest (ROI) within which we measured stiffness included the largest possible portion of a lesion during SWE check. Receiver operating characteristic curves (ROC) were used to determine the cut-off values of SWE quantitative parameters and BI-RADS and to suggest breast lesions as benign or malignant. Based on these cut-off values, each SWE quantitative parameter was combined with BI-RADS. For these combinations, lesions with a positive reading on both BI-RADS and Emax were evaluated as malignant. There were different models of the combination of BI-RADS and a set of parameters. In these models, lesions were evaluated as malignant if both BI-RADS and the set were positive. Model 1 was that the set was counted positive when at least one of the parameters was positive, and model 2 was at least two were positive, and so on. Compare the sensitivity, specificity and the Youden index (sum of sensitivity and specificity minus 1) of SWE quantitative parameters, BI-RADS and their combinations in assessing breast lesions.2. In this study,54 breast lesions which were surgical excision were included. The maximum elasticity (Emax) was obtained, and the color SWE images were classified into four color visual pattern. The tissue sections stained with picric acid-sirius red were used to observe the morphology and arrangement of collagen. The score of collagen morphology (SCM) were determined according to the length, curvature and diameter. The score of collagen arrangement (SCA) were determined according to were there any special arrangement and types of the special arrangement (multilayer, connected into large areas or cellular structure). The total score of collagen (TSC) was the sum of SCM and SCA.Results1. The sensitivity, specificity and the Youden index of Emax were 0.87,0.97 and 0.84, which were higher than other SWE parameters (all P<0.01). The sensitivity, specificity and the Youden index of Emax combined ultrasound BI-RADS were 0.86,0.97 and 0.83, which were higher than other combinations (all P<0.01). The Youden index of model 1 was 0.88, which was the highest (P<0.01). Compared ultrasound BI-RADS alone, the specificity of model 1 was improved from 0.76 to 0.91, without loss of sensitivity.2. The correlation coefficient between Emax and SCM was 0.0.498 (P=0.000), between Emax and SCA was 0.728 (P=0.000), between Emax and TSC was 0.785 (P=0.000). The correlation coefficient between SWE color visual pattern and SCM was 0.662 (P=0.000), between SWE color visual pattern and SCA was 0.584 (P=0.000), between SWE color visual pattern and TSC was 0.680 (P=0.000).Conclusions1. Emax showed the best performance in assessing breast lesions. It can be used as an important quantitative index for benign and malignant breast lesion evaluation. Combining a set of SWE quantitative parameters (Emax, Emean, SD and Eratio), with a positive reading on at least one of the parameters was positive, could imnrove the accuracy of ultrasonography in differentiation of benign from malignant breast lesions, without loss of sensitivity.2. After analyze the correlation between the morphology and arrangement of collagen and SWE features, we found that the morphology and arrangement of collagen maybe the basis of stiffness variance of breast lesions.