Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA.
Department of Radiology, University of Virginia Health System, Charlottesville, Virginia, USA.
World Neurosurg. 2021 Feb;146:e1003-e1011. doi: 10.1016/j.wneu.2020.11.075. Epub 2020 Nov 20.
The latency period from stereotactic radiosurgery (SRS) to obliteration of arteriovenous malformations (AVM) requires continuous imaging surveillance. Magnetic resonance (MR) perfusion is promising for noninvasive monitoring of AVMs after SRS. We studied longitudinal MR perfusion changes of brain AVMs treated with SRS.
Consecutive patients treated for brain AVMs using SRS who had MR perfusion imaging studies performed before and at least once after SRS were studied. We estimated ipsilateral/contralateral brain hemisphere ratios of MR perfusion indexes, including regional cerebral blood flow (rCBF) and relative cerebral blood volume (rCBV), in the AVM nidus, perinidal region, and remote anterior and posterior brain regions.
Eleven patients (6 women; median age, 21 years) underwent SRS (median prescription dose, 18 Gy; range, 12-20 Gy) for brain AVMs (median Spetzler-Martin grade 2 and median volume 4.6 mL). Before the SRS, rCBV and rCBF ratios were significantly higher in the AVM nidus compared with other investigated brain regions (P < 0.001). Median time from SRS to the first and last post-SRS MR perfusion studies was 8 and 35 months, respectively. There was a statically significant decrease of rCBV (P = 0.043) and rCBF (P = 0.036) ratios in the AVM nidus, but not other brain regions, during post-SRS follow-up.
There is a gradual decrease of rCBV and rCBF in the AVM nidus after SRS. MR perfusion imaging is promising for monitoring of hemodynamic changes of AVMs after SRS. Larger studies investigating clinical value of MR perfusion imaging for AVMs after SRS are warranted.
立体定向放射外科（SRS）后动静脉畸形（AVM）闭塞的潜伏期需要连续影像学监测。磁共振（MR）灌注对于 SRS 后 AVM 的非侵入性监测具有广阔的前景。我们研究了 SRS 治疗的脑 AVM 的纵向 MR 灌注变化。
连续接受 SRS 治疗脑 AVM 的患者，在 SRS 前后至少进行一次 MR 灌注成像研究，这些患者被纳入本研究。我们在 AVM 核心、周边区域以及远隔的前、后脑部区域，分别估计了 MR 灌注指数（包括局部脑血流（rCBF）和相对脑血容量（rCBV））的同侧/对侧脑半球比值。
11 例患者（6 例女性；中位年龄 21 岁）因脑 AVM 接受 SRS（中位处方剂量 18 Gy，范围 12-20 Gy）（Spetzler-Martin 分级中位数为 2 级，中位数体积为 4.6 mL）。SRS 前，AVM 核心区 rCBV 和 rCBF 比值明显高于其他研究脑区（P<0.001）。从 SRS 到第一次和最后一次 SRS 后 MR 灌注研究的中位时间分别为 8 个月和 35 个月。在 SRS 后随访期间，AVM 核心区 rCBV（P=0.043）和 rCBF（P=0.036）比值呈静态显著下降，但其他脑区无此变化。
SRS 后 AVM 核心区 rCBV 和 rCBF 逐渐下降。MR 灌注成像有望监测 SRS 后 AVM 的血流动力学变化。需要开展更大规模的研究来评估 SRS 后 MR 灌注成像对 AVM 的临床价值。
