Department of Radiology, Stanford University, Stanford, CA, USA.
Department of Biomedical Engineering, University of California Davis, Davis, CA, USA.
J Cereb Blood Flow Metab. 2022 Aug;42(8):1493-1506. doi: 10.1177/0271678X221083471. Epub 2022 Mar 2.
Cerebrovascular reactivity (CVR) reflects the CBF change to meet different physiological demands. The reference CVR technique is PET imaging with vasodilators but is inaccessible to most patients. DSC can measure transit time to evaluate patients suspected of stroke, but the use of gadolinium may cause side-effects. Arterial spin labeling (ASL) is a non-invasive MRI technique for CBF measurements. Here, we investigate the effectiveness of ASL with single and multiple post labeling delays (PLD) to replace PET and DSC for CVR and transit time mapping in 26 Moyamoya patients. Images were collected using simultaneous PET/MRI with acetazolamide. CVR, CBF, arterial transit time (ATT), and time-to-maximum (Tmax) were measured in different flow territories. Results showed that CVR was lower in occluded regions than normal regions (by 68 ± 12%, 52 ± 5%, and 56 ± 9%, for PET, single- and multi-PLD PCASL, respectively, all p < 0.05). Multi-PLD PCASL correlated slightly higher with PET (CCC = 0.36 and 0.32 in affected and unaffected territories respectively). Vasodilation caused ATT to reduce by 4.5 ± 3.1% (p < 0.01) in occluded regions. ATT correlated significantly with Tmax (R > 0.35, p < 0.01). Therefore, multi-PLD ASL is recommended for CVR studies due to its high agreement with the reference PET technique and the capability of measuring transit time.
脑血管反应性 (CVR) 反映了 CBF 变化以满足不同的生理需求。参考 CVR 技术是使用血管扩张剂的 PET 成像，但大多数患者无法接受。DSC 可以测量通过时间来评估疑似中风的患者，但使用钆可能会引起副作用。动脉自旋标记 (ASL) 是一种用于 CBF 测量的无创 MRI 技术。在这里，我们研究了使用单和多个后标记延迟 (PLD) 的 ASL 来替代 PET 和 DSC 进行 CVR 和在 26 例烟雾病患者中的通过时间映射的效果。使用同时进行的 PET/MRI 采集乙酰唑胺图像。在不同的血流区域测量 CVR、CBF、动脉通过时间 (ATT) 和最大时间 (Tmax)。结果表明，闭塞区的 CVR 低于正常区（分别为 68 ± 12%、52 ± 5%和 56 ± 9%，用于 PET、单 PLD 和多 PLD PCASL，均 p < 0.05）。多 PLD PCASL 与 PET 相关性稍高（在受影响和未受影响的区域分别为 CCC = 0.36 和 0.32）。血管扩张导致闭塞区 ATT 减少 4.5 ± 3.1%（p < 0.01）。ATT 与 Tmax 显著相关（R > 0.35，p < 0.01）。因此，由于多 PLD ASL 与参考 PET 技术具有较高的一致性，并且能够测量通过时间，因此建议用于 CVR 研究。
