Acoustic Radiation Force Impulse Elastography For The Application Of The Differential Diagnosis In Benign And Malignant Breast Mass

Objective: Acoustic radiation force impulse(ARFI) elastography is a quantitative technique to measure of tissue stiffness. The study was aimed to assess the value of ARFI for identification benign and malignant breast mass.Methods: This research included 102 female patients who were carried out breast ultrasound and be confirmed by pathology after surgery, aged from 12 to 82 years old, average(47.62±14.13)years old. The mass size range from 0.76 to 11.23 cm, average of(2.74±1.81)cm. Single mass in 71 patients and multiple mass in 31 people in the research. 42 benign mass and 64 malignant mass be confirmed by pathology.Siemens S2000 color doppler ultrasonic diagnostic apparatus were used for application, and equipped with ARFI technology which can detect virtual touch tissue quantification and get the mass of shear wave velocity, 9L4 multifunctional linear array probe was used, the frequency range of 7-9 MHz. All patients took supine, fully exposed breast, routine ultrasound examination and ARFI measurement were performed respectively.The total mass were evaluated using traditional ultrasound examination and color doppler ultrasound, the parameters include the size of breast mass, position, aspect ratio, boundary, internal echo and calcification features, single or multiple. The color doppler ultrasonic was applied for the graphical blood flow of the mass and small artery blood flow spectrum within the mass, the resistance of mass, thus for BI-RADS classification.The qualitative and quantitative measurement of breast mass, the normal breast tissue surrounding the mass at the same side and the mass of different depth were assessed using Virtual Touch Quantification(VTQ) imaging, then went to VTQ measurement model, probes shoud be perpendicular to organization, and lightly touch with the breast for it’s weight, any external force must be avoided, images were collected and saved, the parameters, such as shear wave velocity, SWV value were recorded, some mass showed SWV values for x.xxm/s that determines the amount of value should be combined with VTI image. Three times should be measured in each mass of different depth and the normal breast tissue surrounding the mass, the average was calculated. Parameters with mean±standard deviation were adopted SPSS 21.0 software and to compare with the pathology results.These comparisons that is between with group of benign and malignant mass, the internal area and the adjacent breast tissue, the mass different depth with normal glands SWV value, the same lesion SWV value of different depth are made rank-sum test when P<0.05 was statistically significant. The ROC curve was depicted according to the results of surgical pathology, diagnostic criteria, for differentiating benign from malignancy in breast mass of the critical value, according to the area under the curve(AUC) concluded its sensitivity, specificity, accuracy, positive predictive value and negative predictive value. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value are compared to separate ultrasonic BI-RADS classification result, that is measured by ultrasonic conventional associated with ARFI value compared with the pathological results.Results:1 Pathology results: Total of 42 mass were approved benign by pathology and total of 64 mass were approved malignant by pathology.2 The acoustic radiation force impulse imaging results: come to the following conclusions:(1)The SWV value differences of different positions inside benign mass were statistically significant respectively, and different positions of size: deep>middle>shallow(P<0.05 respectively).(2) The SWV value differences of shallow and middle groups, shallow and deep groups inside malignant mass were statistically significant respectively, and different positions of size: deep>shallow, middle>shallow(P<0.05 respectively).(3) There were no statistically significant between the SWV value differences of middle and deep groups inside malignant mass(P=0.594).(4) ROC curve analyses showed that the AUC for the SWV was 0.906 in differentiating benign from malignant breast mass, there were statistically significant. The best cutoff points were 6.27m/s for SWV, the sensitivity, specificity and accuracy were 85.9%, 95.2%, 89.6% respectively, positive predictive value and negative predictive value were 96.4%, 81.6%respectively.3 With pathologic results as the gold standard, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value measured by BI-RADS classification of conventional ultrasonic joint ARFI were higher than measured by BI-RADS classification of single conventional ultrasonic, repectively.Conclusion: This study shows that ARFI technology provides quantitative and qualitative information about the tissue stiffness, which provides a new useful tool for identification of benign and malignant breast mass. ARFI technology with conventional ultrasound for BI-RADS classification is helpful to improve the diagnostic rate of benign and malignant breast mass, and it is the beneficial complement of conventional ultrasonic breast, and it provides more valuable information for tumor ultrasound identification, and it provides more basis for clinical diagnosis and treatment plan.