Thyroid Nodule Ultrasound Elasticity Imaging Studies

OBJECTIVE:1. To evaluate the utility of ultrasound elastography in the diagnosis of thyroid nodules, and compare it with conventional ultrasound.2. To explore the interobserver agreement of Elastisity Score system and intraobserver agreement of sonographer in the measurement of strain ratio obtained by ultrasound elastography.METHODS:The study prospectively evaluated109nodules in89pateints who were refered for operation From June2012to February2013. The patients underwent ultrasound elastography (UE) and conventional ultrasound (CU) before operation. The sensitivity, specificity, accuracy, positive and negative predictive values for UE and CU were assessed using histopathological examination as the gold standard. Additionally, diagnostic accuracy was further evaluated according to the size of the nodules. The interobserver agreement of elastisity score system was measured using kappa statistics.Strain ratio of99thyoid nodules were measured obtained by ultrasound elatography. The best cut-off of strain ratio was determined. The sensitivity, specificity, accuracy, positive and negative predictive values for strain ratio were calculated for differential of benign and malignant thyroid nodules using histopathological examination as the gold standard. Strain ratio of99thyoid nodules were measured by the the same sonographer twice in interval of one month who was blinded to the patients’pathologic findings. Bland and Altman’s graphical approch was utilized to investigate the intraobserver agreement.RESULTS:Among the109thyroid nodules included,52(48%) malignant nodules and57(52%) benign ones were confirmed by pathologic diagnosis. Elasticity score system was higher than conventional ultrasound in terms of sensitivity (96.1%vs.80.7%), accuracy (89.9%vs.82.5%), positive predictive value (84.7%%vs.82.3%), and negative predictive value (96%vs.82.7%). The area under the ROC curve demonstrated minor differences between Elasticity score system and conventional ultrasound with no statistical significance (0.902and0.825, respectively).Of99thyroid nodules included,48malignant nodules and51benign ones were confirmed by pathology. The strain ratio of malignant nodules was significantly higher than that of benign ones (3.82±0.84vs.1.62±0.67, P<0.01). The cut-off point for strain ratio was set as2.25. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value were95.8%,84.3%,89.9%,85.2%and95.6%respectively. The area under the curve of strain ratio was0.940, higher than that of elasticity score system (0.902) and conventional ultrasound (0.825).CONCLUSIONS:1. The sensitivity of elasticity score system and strain ratio was higher than that of conventional ultrasound in differentiating malignant from benign thyroid nodules, while specificity was similar.2. Ultrasound elastography was helpful for the diagnosis of thyroid microcarcinoma.3. UE plays important role in thyroid nodules’ diagnosis, and the diagnostic performance is improved when combined with CU.4. Good consistency was observered for the inerobserver agreement of Elasticity Score and intraobserver agreement of strain ratio. OBJECTIVE:To evaluate the diagnostic value of elastography and conventional ultrasound for the differentiation of benign and malignant nodeules in Hashimoto thyroiditis.METHODS:The study prospectively evaluated43nodules in38pateints in Hashimoto thyroiditis.with thyroid nodules who were refered for operation. The patients underwent elastography and conventional ultrasound before operation. The sensitivity, specificity, accuracy, positive and negative predictive values for elastography and conventional ultrasound were assessed using histopathological results as the gold standard.RESULTS:Among the43thyroid nodules studied, pathology confirmed29(67.4%) malignant nodules and14(32.6%) benign ones. The diagnostic performance of elasticity score system and conventional ultrasound is as follows:sensitivity (86.2%vs.96.6%), specificity (71.4%vs.42.9%), accuracy (81.4%vs.79%), positive predictive value (86%vs.77.8%), and negative predictive value (71%vs.85.7%). The area under the receiver operating characteristic (ROC) curve, demonstrated only minor differences between elastography and conventional ultrasound.CONCLUSIONS:The diagnostic accuracy of elatagraphy and conventional ultrasound in differentiating benign from malignant nodules in Hashimoto thyroiditis is similar, while specificity of elasticity score system is higher than that of conventional ultrasound.