| Objective: Ultrasound elastography has been widely used to identify the benign and malignant breast lesions,especially the shear wave elastography(SWE).The effectiveness of SWE has been confirmed by many studies.With the in-depth research of ultrasound elastography,Evans and Tozaki have reported that the surrounding tissues of malignant breast lesions were harder than internal tissues for the first time,which is called the “stiff rim” sign.But there is no study analysing the value of "stiff rim sign" in the differential diagnosis of benign and malignant breast lesions.The purpose of this study is to compare the hardness of surrounding tissues of benign breast lesions with that of malignant breast lesions,and to evaluate the diagnostic value of a series of elastic modulus at the peripheral tissues,and to assess interobserver consistency of quantitative assessment of the "stiff rim" sign in the diagnosis of benign and malignant breast lesions.Methods: This study included 200 female patients with 201 breast lesions confirmed by histopathology in Shenzhen Second People’s Hospital from June to November in 2017.All lesions were examined with shear wave elastography after routine two-dimensional gray scale ultrasound examination.The edge of the lesion was outlined by tracing.The ultrasonic instrument Resona 7 was produced by Mindray(Mindray,Shenzhen,China).The Resona 7 is equipped with the function of "shell" which was used to obtain the elastic modulus of tissue in the 1mm,2mm,and 3mm regions outside the border of lesion,including maximum elastic modulus(Emax),mean elastic modulus(Emean),minimum elastic modulus(Emin),and elastic modulus standard deviation(Esd).We compared the differences of the above elastic modulus values in the benign and malignant groups.The histological diagnostic results were as gold standard.Receiver operating characteristic curve(ROC)was drawn to evaluate the diagnostic efficiency of elastic modulus values,to determine the optimal cut-off value of elastic modulus values,and to analyse the consistency between observers.Results: When "shell" was set as 1mm,2mm,and 3mm,the Emax,Emean,and Esd of the malignant group were higher than those of benign group.And the difference was significant(P=0.000).When "shell" was 1mm,the cut-off values for Emax,Emean,and Esd are 88.94 kPa,25.87 kPa,and 17.85 kPa.The area under the curve(AUC)is 0.983,0.917,and 0.963 respectively.When "shell" was 2mm,the cut-off values for Emax,Emean,and Esd are 96.59 kPa,25.95 kPa and 18.17 kPa.The AUC is 0.993,0.950,and 0.987 respectively.When "shell" was 3mm,the cut-off values for Emax,Emean,and Esd are 96.59 kPa,23.32 kPa,and 17.77 kPa.The AUC is 0.998,0.962,and 0.996 respectively.Whether "shell" is 1mm,or 2mm and 3mm,the Emax has the maximum AUC with statistical significance(P<0.01).In addition,when "shell" was 2mm,the diagnostic efficiency of Emax is best.As for the ineterobserver variability,the intraclass correlation coefficient(ICC)for two ultrasonic doctors was greater than 0.75.And most of the scattered points in the Bland-Altman map were within the 95% conformance boundary.The quantitative evaluation of "stiff rim" sign based on shear wave elastography has high interobserver agreement.Conclusion: The measurement of the stiffness of tissues around the lesions of the breast by shear wave ultrasound elastography could be used to quantitatively evaluate "stiff rim" sign.This quantitative assessment of whether the lesion has "stiff rim" sign is simple and easy.It not only has high sensitivity and specificity,but also a good consistency among observers.So it could be a new method of differentiating benign and malignant breast lesions. |
PDF Full Text Request