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

项目摘要 脑血管疾病(CVD)以大血管狭窄或闭塞为主要原因之一 在所有社会中，死亡和残疾给全世界造成了巨大的社会经济负担。定量脑 在临床检查的不同阶段越来越多地使用灌注图，包括评估 急性和超越受影响血管区域的微循环，指导医学和介入治疗， 预测和纵向随访。含[150]-水的PET被认为是 脑血流量(CBF)测量，但比CT和MRI更难用于临床血管评估 疾病。临床MR灌注成像的主要方法是动态磁化率对比灌注加权 成像(DSC-PWI)。对于患有大血管闭塞疾病的患者，准确的脑血流定量需要 对长时间动脉传输延迟不敏感的去卷积技术。动脉自旋标记(ASL)能力 在不依赖外源性造影剂的情况下估计绝对脑血流量提供了一种非侵入性、更 在非急性情况下，定量的，通常是首选的DSC-PWI替代方案，特别是当有 Gd对比剂禁忌症。ASL方法通常在以下位置应用空间选择性标记模块 供血动脉距离显像区较远。推荐临床使用的标准化ASL技术 应用的是单延迟伪连续ASL(PCASL)方法，该方法对 延迟的运输时间。新开发的速度选择性动脉自旋标记(VSASL)可以最大限度地缩短时间- 延迟灵敏度，但由于使用了基于饱和度的标签模块，因此信噪比较低。我们 最近开发的基于傅里叶变换的速度选择反转(FT-VSI)脉冲序列允许 对灌注信号的敏感度更高，对梯度缺陷的免疫力更强。本研究的目的是 首先在健康人中进一步改进VSASL技术(目标1)；然后评估VSASL技术的重复性和 VSASL在健康人中的敏感性(目标2)；最后评估和验证VSASL在大脑血管疾病患者中的应用。 血管狭窄闭塞型CVD(目标3)。拟议的VSASL技术预计将显示临床价值，而不是 不仅对大脑，而且对身体的其他部分，特别是对儿童、孕妇和患者有利 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.