| ObjectiveVirtual touch tissue quantification (VTQ) of acoustic radiation forceimpulse(ARFI) is a new quantitative technique to measure tissue stiffness. Theaim of this study was to evaluate sensitivity and specificity of AcousticRadiation Force Impulse Imaging(ARFI) in differentiation of thyroid nodulesand compare with conventional ultrasound.MethodsOne-hundred-thirty-six nodules in128patients were available for analysis.All the thyroid lesions were analyzed pathologically after surgery. All thyroidlesions were examined by VTQ to analyze their elasticity after conventionalultrasound. he tissue stiffness for VTQ was expressed as shear wave velocity(SWV)(m/s) and shear wave velocity ratio (SWR). Receiver-operatingcharacteristic curve (ROC) analyses were performed to assess the diagnosticperformance. The areas under ROC curve of two-dimensional ultrasound and VTQwere compared. by Student’s t-test (two tailed, equal variance). p<0.05wereconsidered to be statistically significant.Results1. in102benign nodules,14(13.7%) lesions surrounded by halos;41(40%)lesions with microcalcification;97(95.1%) lesions showed hypoechoic echo;7(6.8%) lesions of the anteroposterior to transverse ratio>1;37(36.2%) lesionsof the internal blood flow signals. Of32malignant nodules,3(8.8%) lesionssurrounded by halos;12(35.4%) lesions with microcalcification;33(97.9%)lesions showed hypoechoic echo;19(55.8%) lesions of the anteroposterior totransverse ratio>1;21(61.7%) lesions of the internal blood flow signals.ROC analyses indicated that the area under the curve was0.725for the US. The sensitivity, specificity, Youden,s index of US in differentiating betweenmalignant andbenign nodules were62.8%,81.3%，0.441,respectively based onthe cutoff point as four point.2. The SWVs of benign and malignant thyroid nodules were(2.37±0.38)m/sand (3.93±1.96) m/s respectively (t=4.907， p=0.000). The meanSWV ratios(SWR) between each nodule and the adjacent thyroid tissue were1.15±0.28for benign and1.77±0.69for malignant nodules (t=4.512， p=0.000).The sensitivity, specificity, positive predic-tive values, negative predictivevalues and accuracy of SWV in differentiating between malignant andbenignnodules were81.4%，82.1%，58.6%，92.2%and80.8%respectively based on thecut off point as2.75m/s. Those of SWR were69.8%，89.3%，67.6%,89.2%and83.8%based on the cut off point as1.32. ROC analyses indicated that the areaunder the curve was0.868(95%CI:0.762,0.941)(p=0.000) for SWV and0.813(95%CI:0.687,0.901)(p=0.000) for the SWR. There is no significant differenceof the two method was compared by Student’s t-test(p>0.20).3. ROC analyses indicated that the area under the curve was0.868(standard error0.040)(p=0.000) for SWV and0.725(standard error0.045)(p=0.001) for the US. The diagnostic accuracy rate of SWV wasstatistically higher than that of US (Z=2.897,p <0.004).ConclusionVTQ of ARFI technology provides the quantitative information of thyroidtissue elasticity andhas high accuracy rate in differentiating between malignantand benign nodules. The diagnostic performance of VTQ is higher than that ofconventional ultrasonography(US). It is a useful complement for US。... |
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