Velocity-Selective Arterial Spin Labeling based Perfusion Mapping for Cerebrovascular Diseases

项目摘要 大血管狭窄或闭塞性脑血管疾病（CVD）是导致脑血管疾病的主要原因之一， 死亡和残疾在所有社会中造成了巨大的社会经济负担。定量脑 灌注映射越来越多地用于临床检查的不同阶段， 急性和其他受影响血管区域的微循环，指导医疗与介入治疗， 测量和纵向随访。含[15 O]-水的PET被视为以下物质的参比标准品： 脑血流量（CBF）测量，但在临床评价血管病变方面不如CT和MRI 疾病临床MR灌注成像的主要方法是动态磁敏感对比剂灌注加权成像 DSC-PWI。对于患有大血管闭塞性疾病的患者，准确的CBF定量需要 去卷积技术对长动脉传输延迟不敏感。动脉自旋标记（ASL）能力 估计绝对CBF而不依赖于外源性造影剂提供了一种非侵入性的， 在非急性情况下，定量，通常是DSC-PWI的首选替代方案，特别是当存在 钆造影剂禁忌症。ASL方法通常将空间选择性标记模块应用于 供应远离成像体积的动脉。推荐用于临床的标准化ASL技术 单延迟伪连续ASL（PCASL）方法，已知其对 延迟的运输时间。新开发的速度选择性动脉自旋标记（VSASL）可以最大限度地减少时间- 延迟灵敏度，但是由于使用基于饱和的标记模块而遭受低信噪比。我们 最近开发的基于傅里叶变换的速度选择性反演（FT-VSI）脉冲串，其允许 对灌注信号有更高的灵敏度，对梯度缺陷有更好的免疫力。本研究旨在 首先，进一步完善健康人的VSASL技术（目标1）;然后评估重现性， VSASL在健康人中的敏感性（目的2）;最后评估和验证VSASL在大- 血管狭窄闭塞性CVD（Aim 3）。预计拟议的VSASL技术将显示出临床价值， 不仅对大脑，而且对身体的其他部位，特别是对儿童，孕妇和患者有益 患有糖尿病或肾功能受损。

Project Abstract Cerebrovascular diseases (CVD) with large-vessel stenosis or occlusion as one of the leading causes of death and disability in all societies, impose enormous social-economic burden worldwide. Quantitative cerebral perfusion mapping is increasingly utilized at different stages of clinical workup, including evaluation of the microcirculation of affected vascular territories acutely and beyond, guiding medical vs. interventional therapy, prognostication, and longitudinal follow-ups. PET with [15O]-water is considered as the reference standard for cerebral blood flow (CBF) measurement but is less accessible than CT and MRI for clinical evaluation of vascular diseases. The mainstay of clinical MR perfusion mapping is dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI). For patients with large vessel occlusive diseases, accurate CBF quantification requires a deconvolution technique that is insensitive to long arterial transit delay. The ability of arterial spin labeling (ASL) to estimate absolute CBF without relying on exogenous contrast agents provides a non-invasive, more quantitative, and often preferred alternative to DSC-PWI in the non-acute setting, particularly when there is contraindication to Gadolinium contrast. ASL methods typically apply spatially selective labeling modules at supplying arteries distant from imaging volumes. The standardized ASL technique recommended for clinical applications is the single-delay pseudo-continuous ASL (PCASL) method, which is known to be sensitive to delayed transit time. Newly developed velocity-selective arterial spin labeling (VSASL) can minimize the time- delay sensitivity but suffers low signal-to-noise ratio due to the use of saturation-based labeling modules. We recently developed Fourier transform based velocity-selective inversion (FT-VSI) pulse trains that allows higher sensitivity to perfusion signal and better immunity to gradient imperfection. The purpose of this study is first to further refine VSASL techniques in healthy people (Aim 1); then to assess the reproducibility and sensitivity of VSASL in healthy people (Aim 2); and finally to evaluate and validate VSASL in patients with large- vessel steno-occlusive CVD (Aim 3). The proposed VSASL techniques are expected to show clinical values not only for the brain, but also for the rest of the body, and especially benefit children, pregnant women, and patients with diabetes or impaired kidney function.