MON-505 Quantitative Characteristics and Sonographic Patterns Before and After Thyroid Radiofrequency Ablation

Although most thyroid nodules (TNs) are benign and require only serial observation, some may need treatment for symptoms. Radiofrequency ablation (RFA) has been used and shown to be a promising and well-tolerated new approach. The efficacy of RFA is evaluated by using parameters such as volume reduction ratio (VRR), and cosmetic or symptomatic improvement. However, no index is now available to predict the therapeutic success before RFA. And apart from size reduction, little is known about their ultrasonography (US) appearances after RFA. The purpose of this study was to 1) assess the effectiveness of single session RFA treatment on volume reduction 2) determine if quantitative US characteristics are correlated to the VRR 3) demonstrate the US characteristics from the baseline and during the follow-up. Quantification of characteristics was performed using commercial software. The CAD software classified nodules into the 2015 ATA sonographic patterns and TIRADS categories. All patients underwent a single treatment session and with significant improvement in cosmetic and pressure symptoms. It shows that there is a direct correlation between the initial tumor size/cyst component percentage and VRR. The US characteristics are significant different after RFA, and the tumors were categorized to more suspicious ATA patterns and had higher TIRAD scores. In conclusion, RFA is effective on volume reduction and US characteristics correlated with therapeutic success. Post RFA US features may potentially mislead and clinicians should always keep in mind.