Purpose The aim of this study was to evaluate the decrease of benign thyroid nodules after bipolar radiofrequency ablation (RFA) in a 3-month follow-up using a multiple overlapping shot technique ('MOST'). Methods A total of 18 patients with 20 symptomatic benign thyroid nodules (17 cold nodules, 3 hyperfunctioning nodules) were treated in one single session by bipolar RFA. Bipolar ablation was performed using MOST. The nodule volumes were measured prior to ablation and 3 months after the procedure using ultrasound. The population consisted of either solid (>80% solid tissue within the volume of interest), complex, or cystic nodules (<20% solid tissue within the volume of interest). Results Bipolar RFA resulted in a highly significant (p < 0.0001) decrease of nodule volume (ΔV), median 5.3 mL (range 0.13-43.1 mL), corresponding to a relative reduction in mean of 56 ± 17.9%. Median initial volume was 8 mL (range 0.48-62 mL); 3 months after ablation a median volume of 2.3 mL (range 0.3-32 mL) was measured. Nodule growth ≥50% occurred in 70% (14 nodules). At the follow-up no complications such as infections, persisting pain, nerve injuries or immunogen stimulation occurred. Patients with cold nodules (15) remained euthyroid, with hyperfunctioning nodules either euthyroid (2) or latent hypofunctional (1). Conclusion The use of bipolar RFA is an effective, safe and suitable thermoablative technique to treat benign thyroid nodules. Combined with the multiple overlapping shot technique it allows sufficient ablation.

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Purpose: To determine the safety and efficacy of bipolar radiofrequency ablation (RFA) in benign thyroid nodules. Methods: 23 patients with 24 symptomatic benign thyroid nodules (21 regressive, 3 adenomas) ranging in volume from 0.5 to 112?ml (mean ? sd: 18???24.4?ml) underwent bipolar RFA. Pain during the procedure was measured on a 10-point scale. Side-effects revealed by ultrasound or patients? complaints were documented. Periablative efficacy was measured 24 hours after RFA as change (?) in serum thyreoglobulin (Tg) and sonographic criteria (echogenity, Doppler blood flow and elasticity) categorized on a 3-point scale (echogenity, Doppler blood flow) or 4-point scale (elasticity). Efficacy in the 3 autonomous adenomas was measured as normalization of 99?mTc-pertechnate scintigraphy. Results: Bipolar RFA was well tolerated by all patients with a median pain score of 3???1.5 (range: 1???7). Side-effects were hematomas in 4 of 23 patients (17?%). Bipolar RFA resulted in a significant (p?

Zusammenfassung ▼Hintergrund: Mikrowellenablationen (MWA) stellen eine neuartige thermoablative Behandlung für benigne Schilddrüsenknoten dar. Ziel war es, die benötigte Energie pro ml Volumenreduktion zu benutzen, um die benötigte Energie für ein volume-of-interest (VOI) abschätzen zu können. Methode: 25 Patienten mit 25 Knoten (6 solide, 13 komplex und 6 zystisch) wurden durch MWA behandelt. Die übertragene Energie (E) wurde mit der Volumenveränderung (Δ V) nach 3 Monaten korreliert. Der Energiebedarf pro ml Volumenreduktion wurde durch E/Δ V bestimmt. Ergebnisse: MWA zeigte eine signifikante (p < 0,0001) Volumenreduktion (Δ V) im Mittel von 12,4 ± 13,0 ml (range: 1,5 -63,2 ml) und eine relative Reduktion von 52 ± 16 % (range: 22 -77 %). Es zeigte sich eine positive Korrelation zwischen E und Δ V (r = 0,82; p < 0,05). Die mittlere E/Δ V war 1,52 ± 1,08 (range: 0,4 -4,6) kJ/ml für alle Knoten und 2,30 ± 1,5 (0,9 -4,6); 1,5 ± 0,9 (0,4 -3,6); 0,75 ± 0,25 (0,4 -1,2) kJ/ml für solide, komplexe und zystische Knoten mit einer signifikanten Differenz der in E/Δ V zwischen soliden und zystischen Knoten (p < 0,03 Abstract ▼Purpose: Microwave ablation (MWA) represents a novel thermal ablative treatment of benign thyroid nodules. The aim was to determine the energy required per ml volume reduction in order to match the required energy to the volume-of-interest (VOI). Materials and Methods: 25 patients with 25 nodules (6 solid, 13 complex and 6 cystic) were treated by microwave ablation (MWA). The transmitted energy (E) was correlated with the volume change (Δ V) after 3 months. The energy required per ml volume reduction after 3 months was calculated by E/Δ V. Results: MWA resulted in a significant (p < 0.0001) volume reduction (Δ V) with a mean of 12.4 ± 13.0 ml (range: 1.5 -63.2 ml) and relative reduction of 52 ± 16 % (range: 22 -77 %). There was a positive correlation between E and Δ V (r = 0.82; p < 0.05). The mean E/Δ V was 1.52 ± 1.08 (range: 0.4 -4.6) kJ/ml for all nodules and 2.30 ± 1.5 (0.9 -4.6), 1.5 ± 0.9 (0.4 -3.6), 0.75 ± 0.25 (0.4 -1.2) kJ/ ml, respectively, for solid, complex and cystic nodules with a significant difference in E/Δ V for solid and cystic (p < 0.03). Conclusion: The energy required per volume depends on the nodule consistency. Solid nodules require more energy than cystic ones. The estimation of the energy needed per volume-of-interest as an additional parameter should help to avoid under-or overtreatment. Key Points:▶ The estimated required energy for a volumeof-interest depends on the nodule consistency ▶ In solid nodules a higher energy transmission than in cystic nodules is recommended ▶ The energy transmission as an additional marker to ultrasound is helpful for improving periprocedural monitoring This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.