Integration of rotational angiography enables better dose planning in Gamma Knife radiosurgery for brain arteriovenous malformations
Integration of rotational angiography enables better dose planning in Gamma Knife radiosurgery for brain arteriovenous malformations
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DOI：
10.3171/2018.7.gks181565
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发表时间：
2018-12-01
影响因子：
4.1
通讯作者：
Saito, Nobuhito
中科院分区：
文献类型：
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作者：
Hasegawa, Hirotaka;Hanakita, Shunya;Saito, Nobuhito
目的 在伽玛刀放射外科 (GKS) 治疗动静脉畸形 (AVM) 中，CT 血管造影 (CTA)、MRI 和数字减影血管造影 (DSA) 通常用于定义病灶。尽管使用旋转血管造影 (RA) 可以以高分辨率可视化 AVM 血管结构，但将 RA 整合到 GKS 治疗计划过程中的功效尚未阐明。 方法 使用从作者所在机构接受 GKS 治疗的连续 25 名 AVM 患者收集的数据，两名神经外科医生在 RA 整合之前和之后独立为每位患者制定治疗计划。对于所有患者，治疗前均进行 MR 血管造影、对比 T1 成像、CTA、DSA 和 RA。测量 RA 积分之前 (PIVB) 和之后 (PIVA) 的处方等剂量体积。出于参考目的，每个病灶的参考目标体积 (RTV) 由另外两名独立于计划外科医生的医生确定，并建立了 PIV (RTVPIV) 覆盖的 RTV。每位神经外科医生在 RA 整合前后测量治疗不足的体积比 (UVR)、过度治疗的体积比 (OVR) 和帕迪克适形指数 (CI)，分别计算为 RTVPIV/RTV、RTVPIV/PIV 和 (RTVPIV)(2)/(RTV x PIV)，并对每个点的外科医生值进行平均。 Wilcoxon 符号秩检验用于比较 RA 集成之前和之后获得的值。计算每位患者的平均 UVR (%Delta UVRave)、OVR (%Delta OVRave) 和 CI (%Delta CIave) 从 RA 整合之前到之后的百分比变化，计算公式为（[RA 整合后的值]/[RA 整合之前的值] - 1）x 100。使用 Wilcoxon 符号秩检验检查既往病史和这些百分比变化值之间的关系。 结果 两位外科医生获得的中位 UVR 平均值， RA 整合前的 OVR 和 CI 分别为 0.854、0.445 和 0.367，RA 整合后的 OVR 和 CI 分别为 0.882、0.478 和 0.463。与 RA 整合前相比，所有变量均显着改善（UVR，p = 0.009；OVR，p < 0.001；CI，p < 0.001）。既往出血与较大的 %Delta OVRave（中位数 20.8% vs 7.2%；p = 0.023）和 %Delta CIave（中位数 33.9% vs 13.8%；p = 0.014）显着相关，但与 %Delta UVRave 无关（中位数 4.7% vs 4.0%；p = 0.449）。 结论 整合 RA由于病灶的可视化更加清晰，纳入 GKS 治疗计划可能会允许更好的剂量计划，因此可以减少治疗不足和浪费辐射。需要进一步研究观察观察到的与 RA 相关的剂量计划改善是否也能改善放射外科结果。
OBJECTIVE In Gamma Knife radiosurgery (GKS) for arteriovenous malformations (AVMs), CT angiography (CTA), MRI, and digital subtraction angiography (DSA) are generally used to define the nidus. Although the AVM angioarchitecture can be visualized with superior resolution using rotational angiography (RA), the efficacy of integrating RA into the GKS treatment planning process has not been elucidated.METHODS Using data collected from 25 consecutive patients with AVMs who were treated with GKS at the authors' institution, two neurosurgeons independently created treatment plans for each patient before and after RA integration. For all patients, MR angiography, contrasted T1 imaging, CTA, DSA, and RA were performed before treatment. The prescription isodose volume before (PIVB) and after (PIVA) RA integration was measured. For reference purposes, a reference target volume (RTV) for each nidus was determined by two other physicians independent of the planning surgeons, and the RTV covered by the PIV (RTVPIV) was established. The undertreated volume ratio (UVR), overtreated volume ratio (OVR), and Paddick's conformal index (CI), which were calculated as RTVPIV/RTV, RTVPIV/PIV, and (RTVPIV)(2)/(RTV x PIV), respectively, were measured by each neurosurgeon before and after RA integration, and the surgeons' values at each point were averaged. Wilcoxon signed-rank tests were used to compare the values obtained before and after RA integration. The percentage change from before to after RA integration was calculated for the average UVR (%Delta UVRave), OVR (%Delta OVRave), and CI (%Delta CIave) in each patient, as ([value after RA integration]/[value before RA integration] - 1) x 100. The relationships between prior histories and these percentage change values were examined using Wilcoxon signed-rank tests.RESULTS The average values obtained by the two surgeons for the median UVR, OVR, and CI were 0.854, 0.445, and 0.367 before RA integration and 0.882, 0.478, and 0.463 after RA integration, respectively. All variables significantly improved after compared with before RA integration (UVR, p = 0.009; OVR, p < 0.001; CI, p < 0.001). Prior hemorrhage was significantly associated with larger %Delta OVRave (median 20.8% vs 7.2%; p = 0.023) and %Delta CIave (median 33.9% vs 13.8%; p = 0.014), but not %Delta UVRave (median 4.7% vs 4.0%; p = 0.449).CONCLUSIONS Integrating RA into GKS treatment planning may permit better dose planning owing to clearer visualization of the nidus and, as such, may reduce undertreatment and waste irradiation. Further studies examining whether the observed RA-related improvement in dose planning also improves the radiosurgical outcome are needed.