Chen Conan, Barnes Ryan A, Bangen Katherine J, Han Fei, Pfeuffer Josef, Wong Eric C, Liu Thomas T, Bolar Divya S
Center for Functional MRI, University of California San Diego, La Jolla, California, USA.
Department of Radiology, University of California San Diego, La Jolla, California, USA.
Magn Reson Med. 2025 Apr;93(4):1516-1534. doi: 10.1002/mrm.30370. Epub 2024 Dec 29.
By leveraging the small-vessel specificity of velocity-selective arterial spin labeling (VSASL), we present a novel technique for measuring cerebral MicroVascular Pulsatility named MVP-VSASL.
We present a theoretical model relating the pulsatile, cerebral blood flow-driven VSASL signal to the microvascular pulsatility index ( ), a widely used metric for quantifying cardiac-dependent fluctuations. The model describes the dependence of the of VSASL signal (denoted ) on bolus duration (an adjustable VSASL sequence parameter) and provides guidance for selecting a value of that maximizes the SNR of the measurement. The model predictions were assessed in humans using data acquired with retrospectively cardiac-gated VSASL sequences over a broad range of values. In vivo measurements were also used to demonstrate the feasibility of whole-brain voxel-wise pulsatility mapping, assess intrasession repeatability of , and illustrate the potential of this method to explore an association with age.
The theoretical model showed excellent agreement to the empirical data in a gray matter region of interest (average value of 0.898 0.107 across six subjects). We further showed excellent intrasession repeatability of the pulsatility measurement ( , ) and the potential to characterize associations with age ( , ).
We have introduced a novel, VSASL-based cerebral microvascular pulsatility technique, which may facilitate investigation of cognitive disorders where damage to the microvasculature has been implicated.
通过利用速度选择性动脉自旋标记（VSASL）的小血管特异性，我们提出了一种测量脑微血管搏动性的新技术，称为MVP-VSASL。
我们提出了一个理论模型，将搏动性的、脑血流驱动的VSASL信号与微血管搏动指数（ ）相关联，微血管搏动指数是一种广泛用于量化心脏依赖性波动的指标。该模型描述了VSASL信号的 （表示为 ）对团注持续时间 （一个可调节的VSASL序列参数）的依赖性，并为选择能使 测量的信噪比最大化的 值提供指导。使用通过回顾性心脏门控VSASL序列在广泛的 值范围内采集的数据，在人体中评估了模型预测。体内测量还用于证明全脑体素级搏动性映射的可行性，评估 的会话内重复性，并说明该方法探索与年龄关联的潜力。
理论模型在感兴趣的灰质区域与经验数据显示出极好的一致性（六名受试者的平均 值为0.898 ± 0.107）。我们进一步展示了搏动性测量的极好的会话内重复性（ ， ）以及表征与年龄关联的潜力（ ， ）。
我们引入了一种基于VSASL的新型脑微血管搏动性技术，这可能有助于对涉及微血管损伤的认知障碍进行研究。
