Quantitative Assessment Of Real-time Shear Wave Elastography Imaging Differenetiating Benign And Malignant Breast Mass

Objective:To investigate the shear wave elastography (SWE) technology for the quantitative analysis of the Emean in normal mammary glands of different age to determine if there is statistical difference, to measure the Emax values, and the Eratio of lesions and the surrounding normal gland, to determine the ROC curve, and to measure the Emax and Eratio value of benign and malignant breast lesions.Methods:1. Real-time ultrasound shear wave elastography examinations were performed on the normal mammary glands for63asymptomatic patients to measure the elasticity Emean. The age groups were≤40years (28cases),>40years (35cases). The t-tests were performed comparing the Emean of pre and post age40groups to see whether there are statistically significant variations.2. We collected the data for eventually into the group of61female patients (63 lesions) for breast surgical treatments in the first Affiliated Hospital, Zhejiang University School of Medicine from December2014to March2015, including40benign lesions and23malignant lesions. The pathology results of the lesions were collected post-surgery or after minimally invasive ultrasound-guided core needle biopsy. All patients underwent conventional ultrasound (US) examination before surgery to measure the lesion locations, shapes, edges, sizes, and the echo and blood flow of the lesion and its surrounding tissues. The lesions were classified according to BI-RADS. Real-time shear-wave elastography examinations for the lesions and the adipose tissue were performed. The Emean of the fat tissues in front of the lesion was obtained, together with the Emax and Eratio of the lesion and the surrounding glands.3. We compared the Emean of the fat layer in front of the lesions, the Emax of the lesions and the Eratio of surrounding glands. We analyzed these three sets of data for both benign and malignant lesions. The ROC curves (receiver operating characteristic curve) were constructed to evaluate the Emax of benign and malignant lesions, the Eratio reference values, and the sensitivity, specificity and accuracy of the diagnosis.Results:1. In these63cases, there is no statistically significant difference in the Emax of the glands of patients pre and post age40.2. The pathology tests showed38benign cases (41lesions),23malignant cases (23lesions). The malignant lesions Emax was82.259±41.370kPa, and the benign lesions Emax was20.973±7.308kPa. There was statistically significant difference (P<0.01) between within the benign and malignant lesions.3. For the subcutaneous fat in front of the breast lesions, the Emean of benign lesions was10.956±3.737kPa, and those of malignant lesions was15.639±5.607kPa. There is a statistically significant (P<0.01) in the Emean of the fat layer in front of the benign and malignant lesions.4. The mean Eratio between lesions and glands for benign lesions was1.588±0.543, and for malignant lesions the Eratio was5.260±2.190. There is a statistically significant difference (P<0.01) in the Eratio between benign and malignant cases.5. Using the SWE quantitative analysis for these breast lesions, with the Emax boundary value of55.8kPa, the area under the ROC curve (AUC) was0.963, the sensitivity was0.913, the specificity was0.950and the accuracy was0.937. With the Eratio boundary value of3.45, the AUC was0.948, the sensitivity was0.913, the specificity was0.925, and the accuracy was0.921.6. The Emax of the lesion elastic modulus, the Eratio between lesions and glands, and the Emean of the fat in front of the lesions are useful in differentiating benign and malignant cases.Conclusion:1. There is good reproducibility in using the Shear wave elastography to measure the breast-tissue elastic modulus in the normal population in different age groups. This study showed that there is no significant difference between the Emean of the mammary glands for different ages groups. There is a statistically significant difference (P<0.01) in the Eratio between benign and malignant cases. Therefore, the mammary gland Eratio of the breast mass can be used as a reference.2. The Eratio between mammary lesions and glands will help to identify benign and malignant breast cancer, which takes into account of the variations under different breast backgrounds. When the mass Emax exceeds55.8Kap or when the Eratio exceeds3.45, the quantitative elastography has high specificity and accuracy in cancer diagnosis.3. Quantitative elastic modulus can improve the sensitivity of diagnosing benign and malignant lesions, the quantitative data can objectively reflect the compressibility of tissues, and facilitate the research of ultrasonic tissue characterization. It may have a good potential for clinical application.