The Application Of Real-Time Elastography In Clinical Differentiation Diagnosis Of Benign And Malignant Thyroid Nodules

Objective To establish the Logistic regression model based on the valuable indexes of ultrasonic solitary thyroid nodules and evaluate Real-time Tissue Elastography (RTE) in clinical differentiation diagnosis of benign and malignant thyroid nodules.Materials and Methods The study included 95 consecutive patients with thyroid solitary nodular were examined with B-mode, Color Doppler ultrasonography, RTE and STA during May to October 2010. Examinations were performed using二郎神, HI VISION-900 (Hitachi Medical Corporation, Japan) and 6.0～13.0MHz multifrequency linear probe. With the patient lying in the supine position used for conventional US examination (B-mode), including size, shape, margins, echogenicity, calcification, halo of the noudules, the situations of Color Doppler flow in and around the nodules; and Superior Thyroid Artery (STA) examination, which the lesion lies in, including peak systolic velocity (S), diastolic velocity (D), Pulsatility index (PI) and resistance index (RI), S/D ratio. Measuring relatively hardness between thyroid lesion area and normal tissues, and obtained the Strain Ratio (SR) of the elasticity score. After the activation of elastography, continuous manual compression was applied to the target region, perpendicular to the lesions, until tissue resistance was detected. Observe the US and UE using dual real-time dynamic display until constant 3 waves were appeared on the screen. Freeze it, and measure the SR at the bottom of the waves. Focal area should be including the whole lesion as much as possible and at least twice area in normal tissue around the lesion. The SR is bigger, the lesion is harder.Pathological diagnosis as a golden standard, a logistic model was obtained on the basis of ultrasonographic features. A receiver operator characteristic (ROC) curve was constructed to assess the performance of the logistic model. Results Three ultrasonographic features including calcification, echogenicity of lesions, SR of the elasticity score and Superior Thyroid Artery (STA) resistance indexes (RI) were finally entered into the binary Logistic regression. The area under ROC curve(AUC)of SR was 0.908, the sensitivity, specificity and accuracy in RTE were 95.5%, 82.2% and 90.8%, which had significant statistical differences. But combination of SR and RI, the U was 0.456, P<1.96,has no significant differences in statistical.Conclusions The multivariate analysis model of binary Logistic regression can select out the valuable indexes of differential diagnosis of benign and malignant thyroid solitary nodules. SR is more helpful than otherindexes that can assist in the differential diagnosis of thyroid nodules. Combination SR and STA has no significant advantages in the diagnosis of thyroid nodules.