Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Kiel, Germany.
Int J Radiat Oncol Biol Phys. 2021 Jul 1;110(3):745-756. doi: 10.1016/j.ijrobp.2021.01.028. Epub 2021 Jan 27.
Cardiac radioablation is a novel treatment option for therapy-refractory ventricular tachycardia (VT) ineligible for catheter ablation. Three-dimensional clinical target volume (CTV) definition is a key step, and this complex interdisciplinary procedure includes VT-substrate identification based on electroanatomical mapping (EAM) and its transfer to the planning computed tomography (PCT). Benchmarking of this process is necessary for multicenter clinical studies such as the RAVENTA trial.
For benchmarking of the RAVENTA trial, patient data (epicrisis, electrocardiogram, high-resolution EAM, contrast-enhanced cardiac computed tomography, PCT) of 3 cases were sent to 5 university centers for independent CTV generation, subsequent structure analysis, and consensus finding. VT substrates were first defined on multiple EAM screenshots/videos and manually transferred to the PCT. The generated structure characteristics were then independently analyzed (volume, localization, surface distance and conformity). After subsequent discussion, consensus structures were defined.
VT substrate on the EAM showed visible variability in extent and localization for cases 1 and 2 and only minor variability for case 3. CTVs ranged from 6.7 to 22.9 cm, 5.9 to 79.9 cm, and 9.4 to 34.3 cm; surface area varied from 1087 to 3285 mm, 1077 to 9500 mm, and 1620 to 4179 mm, with a Hausdorff-distance of 15.7 to 39.5 mm, 23.1 to 43.5 mm, and 15.9 to 43.9 mm for cases 1 to 3, respectively. The absolute 3-dimensional center-of-mass difference was 5.8 to 28.0 mm, 8.4 to 26 mm, and 3.8 to 35.1 mm for cases 1 to 3, respectively. The entire process resulted in CTV structures with a conformity index of 0.2 to 0.83, 0.02 to 0.85, and 0.02 to 0.88 (ideal 1) with the consensus CTV as reference.
Multicenter efficacy endpoint assessment of cardiac radioablation for therapy-refractory VT requires consistent CTV transfer methods from the EAM to the PCT. VT substrate definition and CTVs were comparable with current clinical practice. Remarkable differences regarding the degree of agreement of the CTV definition on the EAM and the PCT were noted, indicating a loss of agreement during the transfer process between EAM and PCT. Cardiac radioablation should be performed under well-defined protocols and in clinical trials with benchmarking and consensus forming.
心脏放射消融术是一种治疗难治性室性心动过速（VT）的新方法，对于不能进行导管消融的患者也适用。三维临床靶区（CTV）的定义是关键步骤，这个复杂的跨学科过程包括基于电解剖图（EAM）的 VT 底物的识别及其转移到规划计算机断层扫描（PCT）。RAVENTA 试验等多中心临床研究需要对这一过程进行基准测试。
为了基准测试 RAVENTA 试验，将 3 例患者的数据（病历、心电图、高分辨率 EAM、对比增强心脏计算机断层扫描、PCT）发送到 5 个大学中心，用于独立的 CTV 生成、后续结构分析和共识发现。首先在多个 EAM 截图/视频上定义 VT 底物，并手动将其转移到 PCT。然后独立分析生成的结构特征（体积、定位、表面距离和一致性）。随后进行讨论，定义共识结构。
EAM 上的 VT 底物在病例 1 和 2 中在程度和定位上显示出明显的变异性，而在病例 3 中只有较小的变异性。CTV 范围为 6.7 至 22.9cm、5.9 至 79.9cm 和 9.4 至 34.3cm；表面积分别为 1087 至 3285mm、1077 至 9500mm 和 1620 至 4179mm，病例 1 至 3 的 Hausdorff 距离分别为 15.7 至 39.5mm、23.1 至 43.5mm 和 15.9 至 43.9mm。绝对三维质心差异分别为 5.8 至 28.0mm、8.4 至 26mm 和 3.8 至 35.1mm。对于病例 1 至 3，整个过程导致 CTV 结构的一致性指数为 0.2 至 0.83、0.02 至 0.85 和 0.02 至 0.88（理想为 1），以共识 CTV 作为参考。
对于难治性 VT 的心脏放射消融治疗的多中心疗效终点评估需要从 EAM 到 PCT 一致地转移 CTV 方法。VT 底物的定义和 CTV 与当前的临床实践是可比的。在 EAM 和 PCT 上的 CTV 定义的一致性程度方面注意到了显著的差异，表明在 EAM 和 PCT 之间的转移过程中存在一致性的丧失。心脏放射消融术应在定义明确的方案和临床试验中进行，并进行基准测试和达成共识。
