Preliminary Results On Absorption Of Radiofrequency Ablation Lesions Using Real-time Ultrasound Elastography

As a minimally invasive treatment with no scar, no affect on thyroid function,clinical application of ultrasound-guided radiofrequency (RF) ablation of benign thyroidnodules has been on the ascendant. Due to the ultrasound characteristic of simple,convenient, cheap, and real-time, no radiation, etc, it has been recognized as the firstchoice of guised mode and effective evaluation tool of RF ablation. Ultrasoundevaluated the effect of RF ablation of benign thyroid nodules and tumors byconventional two-dimensional ultrasound, color Doppler ultrasound andcontrast-enhanced ultrasound, which can provide the information of the ablation lesionsize, morphology, blood flow, as well as the degree of ablation. After RF ablation, thetissue of solid tumors becomes dry and forms coagulate necrosis, and real-timeultrasound elastography can reflect the tissue’s elasticity by collecting strain informationby using the red-green-blue color imaging technology. Real-time ultrasoundelastography showed the morphology and size of liver ablation lesion, and it evaluatedliver RF ablation effectively[1]. Although the reports on the evaluation of thyroid RFablation lesion using real-time ultrasound elastography showed that during thefollow-up the elasticity score of ablation lesion gradually had a negative trend, no studyhas assessed with further systematic observation and comparative work. Therefore, inthis study, we observed the elasticity score of benign thyroid nodules before and afterRF ablation, discussed the value of real-time ultrasound elastography in RF ablation ofbenign thyroid nodules.Objective: To analyze the change law of elasticity score, investigate therelationship between elasticity score and absorption and explore the feasibility ofassessing absorption by real-time ultrasound elastography over a12month follow-up.Methods: We evaluated88benign thyroid nodules of55patients of treated withRF ablation from February2010to February2012and followed-up12months. Nodulevolume, volume reduction radio (VRR) and elasticity score were evaluated before treatment and during follow-up. Using SPSS13.0statistical software, analyze therelationship between the volume of pro-and post-RF ablation, VRR of post-RF ablation,elasticity score of pro-and post-RF ablation, the post-RF ablation volume and thepost-RF ablation VRR of different elasticity score by repeated variance analysis, thevolume of elasticity score4measured by two-dimensional and elastography by pairedt-test, and the relationship of volume/VRR and elasticity score by correlation analysis.Results: Thyroid nodule elasticity score decreased significantly from3beforeablation to2(P<0.01) at final evaluation. There was no significant difference betweenthe volumes of two-dimensional and elastography of the elasticity score4lesions (P>0.05). In different elasticity score groups, the absorption was different (P <0.05).Conclusion: Real-time ultrasound elastography was effective in evaluatingabsorption of RF ablation of benign thyroid nodules over a12months follow-up. It wasused to evaluate volume if the two-dimensional ultrasound showed not clear. The6thmonth after RF ablation was a critical point to evaluate the therapeutic effect of benignthyroid nodules. Therefore, real-time ultrasound elastography can be used as aneffective tool to evaluate absorption of RF ablation of benign thyroid nodules.