Microwave Ablation of Symptomatic Benign Thyroid Nodules: Energy Requirement per ml Volume Reduction

Abstract

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.

Conspicuousness and recurrence related factors of ultrasound-guided microwave ablation in the treatment of benign thyroid nodules

“…However, Wang et al [ 30 ] indicated that initial volume, vascularity, and the energy per 1 mL reduction in nodular volume were all risk factors for recurrence of benign thyroid nodules treated with ultrasound guided microwave ablation. In addition, Korkusuz et al [ 31 ] revealed that solid nodules require more the energy per 1 mL reduction than cystic and mixed nodules. Therefore, for large volume nodules requiring high power and long time ablation in clinical practice, they are often prone to recurrence.…”

Microwave ablation induces a lower systemic stress response in patients than open surgery for treatment of benign thyroid nodules

“…Of late, microwave ablation has been increasingly used for treatment of benign thyroid nodules with satisfactory outcomes [13,14]. Microwave ablation has its own advantages especially with respect to simplified operation and cosmetic benefits; however, it is not suitable for treatment of larger nodules (diameter >30-40 mm) [15,16].…”

Ultrasound-Guided Thermal Ablation of Thyroid Nodules: Technicalities Progress and Clinical Applications, Especially in Malignant Thyroid Nodules

“…To avoid the occurrence of severe hemorrhage, vessels that are found along the approach route are carefully evaluated using Doppler US (24). Before ablation, local anesthesia with 1% lidocaine is typically injected at the subcutaneous puncture site and the periphery of thyroid nodules to reduce the pain during the skin incision and insertion of an electrode; in instances where cystic components are present, fluid is aspirated before USguided percutaneous ablation (23,(25)(26)(27).…”