From the Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 138-225, Korea (Y.S.K., M.J.P., H.R., H.K.L.); Philips Healthcare, Seoul, Korea (B.K.); and Philips Healthcare, Vantaa, Finland (K.N., M.O.K.).
Radiology. 2014 Feb;270(2):589-600. doi: 10.1148/radiol.13130380. Epub 2013 Oct 28.
To determine whether intraprocedural thermal parameters as measured with magnetic resonance (MR) thermometry can be used to predict immediate or delayed therapeutic response after MR-guided high-intensity focused ultrasound (HIFU) ablation of uterine fibroids.
Institutional review board approval and subject informed consent were obtained. A total of 105 symptomatic uterine fibroids (mean diameter, 8.0 cm; mean volume, 251.8 mL) in 71 women (mean age, 43.3 years; age range, 25-52 years) who underwent volumetric MR HIFU ablation were analyzed. Correlations between tumor-averaged intraprocedural thermal parameters (peak temperature, thermal dose efficiency [estimated volume of 240 equivalent minutes at 43°C divided by volume of treatment cells], and temperature decay rate after sonication) and the immediate ablation efficiency (ratio of nonperfused volume [NPV] at immediate follow-up to treatment cell volume) or ablation sustainability (ratio of NPV at 3-month follow-up to NPV at immediate follow-up) were assessed with linear regression analysis.
A total of 2818 therapeutic sonications were analyzed. At immediate follow-up with MR imaging (n = 105), mean NPV-to-fibroid volume ratio and ablation efficiency were 0.68 ± 0.26 (standard deviation) and 1.35 ± 0.75, respectively. A greater thermal dose efficiency (B = 1.894, P < .001) and slower temperature decay rate (B = -1.589, P = .044) were independently significant factors that indicated better immediate ablation efficiency. At 3-month follow-up (n = 81), NPV had decreased to 43.1% ± 21.0 of the original volume, and only slower temperature decay rate was significantly associated with better ablation sustainability (B = -0.826, P = .041).
The postsonication temperature decay rate enables prediction of both immediate and delayed therapeutic responses, whereas thermal dose efficiency enables prediction of immediate therapeutic response to MR HIFU ablation of uterine fibroids.
确定磁共振（MR）测温仪测量的术中热参数是否可用于预测 MR 引导高强度聚焦超声（HIFU）消融子宫肌瘤后的即刻或延迟治疗反应。
本研究获得了机构审查委员会批准和受试者知情同意。对 71 名女性（年龄 25-52 岁，平均 43.3 岁）的 105 个有症状的子宫肌瘤（平均直径 8.0cm，平均体积 251.8mL）进行了容积式 MR-HIFU 消融，分析了肿瘤平均术中热参数（峰值温度、热剂量效率[估计 43°C 时 240 等效分钟的体积除以治疗细胞体积]和超声后温度衰减率）与即刻消融效率（即刻随访时无灌注体积[NPV]与治疗细胞体积的比值）或消融可持续性（3 个月随访时 NPV 与即刻随访时 NPV 的比值）之间的相关性，采用线性回归分析。
共分析了 2818 次治疗性超声。在 MR 成像的即刻随访（n=105）中，平均 NPV 与肌瘤体积比和消融效率分别为 0.68±0.26（标准差）和 1.35±0.75。较大的热剂量效率（B=1.894，P<0.001）和较慢的温度衰减率（B=-1.589，P=0.044）是独立的显著因素，表明即刻消融效率更好。在 3 个月随访时（n=81），NPV 下降至原始体积的 43.1%±21.0%，只有较慢的温度衰减率与更好的消融持续性显著相关（B=-0.826，P=0.041）。
超声后温度衰减率可预测即刻和延迟治疗反应，而热剂量效率可预测 MR-HIFU 消融子宫肌瘤的即刻治疗反应。
