Endocrinology, Diabetes and Metabolism Department and Center for Thyroid Diseases, A.O. Ordine Mauriziano, Turin, Italy.
Clinic for Nuclear Medicine and Competence Centre for Thyroid Disease, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Bellinzona and Lugano, Switzerland.
Eur Radiol. 2021 Jul;31(7):5189-5197. doi: 10.1007/s00330-020-07532-y. Epub 2021 Jan 6.
Radiofrequency ablation (RFA) is effective in reducing the volume of benign thyroid nodules. However, what parameters can influence the response to RFA is still unclear. The present study aimed to (1) investigate which ultrasound and technical parameters are potential determinants of the volumetric reduction; (2) develop a dose-response model, and (3) analyze the effects of RFA on ultrasound features.
In this retrospective study, three institutions treated patients with benign thyroid nodules according to the same protocol. The technical parameters were power and energy. The 1-year volume reduction ratio (VRR) was the reference standard of the response. The correlations of different parameters with VRR were analyzed and the association between several parameters and a VRR above 50% studied by uni- and multivariate analyses. The probit regression estimated the probability to achieve an effective response.
One hundred fifteen patients were enrolled. The median power was 50 W and median total delivered energy 27,531 J. At 1-year follow-up, the median VRR was 64.0% and 87 (75.7%) nodules showed a VRR above 50%. Among all parameters, only baseline volume, total energy, and energy per volume were independently associated to a VRR > 50% (p = 0.001, p = 0.0178, p < 0.001 respectively). The probit regression analysis demonstrated that delivering 756 J/ml and 2670 J/ml gave a probability of VRR > 50% in 50% and 99% of patients, respectively.
Considering the baseline nodular volume and delivering the adequate energy per volume allow optimizing technical and clinical success.
• The effectiveness of radiofrequency ablation in treating benign thyroid nodules is negatively correlated to the volume of the nodule and positively correlated to the energy delivered per volume. • When planning the treatment, the total energy to deliver can be calculated by using a simple formula: nodular volume × 2670 J.
射频消融（RFA）在缩小良性甲状腺结节体积方面具有显著疗效。然而，目前尚不清楚哪些参数会影响消融效果。本研究旨在：（1）探究哪些超声和技术参数是体积缩小的潜在决定因素；（2）建立剂量反应模型；（3）分析 RFA 对超声特征的影响。
这是一项回顾性研究，三所机构按照相同的方案治疗良性甲状腺结节患者。技术参数为功率和能量。1 年体积缩小率（VRR）为反应的参考标准。分析了不同参数与 VRR 的相关性，并通过单变量和多变量分析研究了几个参数与 VRR 超过 50%的相关性。概率回归估计了实现有效反应的概率。
共纳入 115 例患者。中位功率为 50W，总传递能量为 27531J。在 1 年随访时，中位 VRR 为 64.0%，87（75.7%）个结节的 VRR 超过 50%。在所有参数中，仅基线体积、总能量和能量密度与 VRR>50%独立相关（p=0.001，p=0.0178，p<0.001）。概率回归分析表明，当输送能量密度分别为 756J/ml 和 2670J/ml 时，50%和 99%的患者的 VRR>50%的概率分别为 50%和 99%。
考虑到结节的基线体积和给予适当的能量密度可以优化技术和临床疗效。
（1）射频消融治疗良性甲状腺结节的疗效与结节体积呈负相关，与单位体积内输送的能量呈正相关。（2）在制定治疗计划时，可通过使用简单的公式（结节体积×2670J）计算所需输送的总能量。
