Non-Contrast-Enhanced Velocity-Selective MR Angiography at 3T for Cerebrovascular Diseases

项目摘要 脑血管疾病作为所有社会中死亡和残疾的主要原因之一， 全世界的社会经济负担。脑血管造影在鉴别诊断中起着不可或缺的作用， 神经系统疾病患者的预后前景、治疗管理和治疗后随访 血管病理学，如中风，动脉狭窄， 脑静脉窦血栓形成 、动静脉畸形， 和动脉瘤传统上，基于导管的X射线血管造影术被认为是诊断的金标准。 脑血管评估。对比度增强（CE）MRA允许大空间覆盖，高空间分辨率， 分辨率和快速采集。然而，动脉显影常常被静脉增强所掩盖。在 此外，基于Gd的CE MRA的安全性已受到挑战，因为担心发生肾源性 肾功能受损患者的系统性纤维化（NSF）以及 脑内Gd沉积 即使不存在肾脏疾病 .因此，非对比增强磁共振血管造影（NCE MRA）迅速 以最大限度地降低风险和成本。临床实践中的主要NCE脑MRA是3D时间- 飞行（TOF）方法，已知其具有有限的血管造影覆盖范围和对慢流的不良描绘。 新开发的动脉自旋标记（ASL）MRA可以提供大空间覆盖或4D时间分辨 动态填充动脉MRA。ASL方法的缺点是信号效率降低， 由于减去标记和未标记的血液信号需要两次采集而延长了扫描时间， 以及对运动引起的配准不良的敏感性。我们最近证明了一种新速度的可行性- 选择性（VS）MRA方法在3 T下用于脑部应用，这是一种非减影技术， 大覆盖面和慢流描绘。旨在结合TOF和ASL MRA的有利方面 方法，我们提出了许多技术进步的VS MRA呈现三维动脉造影，静脉造影和 4D时间分辨MRA。本研究旨在 首先进一步发展这些VS脑MRA技术， 目的1：比较血流模型和正常人的3D对比MR动脉造影， 脑静脉窦患者颈动脉或颅内动脉狭窄（Aim 2）和3D VS MR静脉成像 血栓形成（目的3），并最终评价4D时间分辨VS-MRA在AVM或动脉瘤患者中的应用 (Aim 4）。 所提出的NCE VS MRA技术预计不仅对大脑， 对身体的其他部分也有好处， 儿童、孕妇和糖尿病患者或 肾功能受损 .

Project Abstract Cerebrovascular diseases, as one of the leading causes of death and disability in all societies, impose enormous social-economic burden worldwide. Cerebral angiography plays an indispensable role in differential diagnosis, prognosis outlook, therapeutic management, and follow-up after treatment for patients with neurological vasopathology, such as stroke, arterial stenosis, cerebral venous sinus thrombosis , arteriovenous malformation, and aneurysm. Traditionally, catheter-based X-ray angiography has been considered the gold standard for cerebrovascular assessment. Contrast-enhanced (CE) MRA allows large spatial coverage, high spatial resolution, and rapid acquisition. However, arterial visualization are often obscured by venous enhancement. In addition, the safety of Gd based CE MRA has been challenged for the concerns of developing Nephrogenic Systemic Fibrosis (NSF) for patients with impaired kidney function and the reports of Gd deposition in the brain even when no kidney disease is present . Thus non-contrast-enhanced MR angiography (NCE MRA) has rapidly evolved to minimize risk and lower cost. The primary NCE cerebral MRA in clinical practice is the 3D time-of- flight (TOF) method, which is known to have limited angiographic coverage and poor delineation of slow flow. Newly developed arterial spin labeling (ASL) MRA can provide either large spatial coverage or 4D time-resolved MRA with dynamic filling of arteries. The drawback of the ASL methods are the reduced signal efficiency, lengthened scan times due to the required two acquisitions for subtraction of labeled and unlabeled blood signal, and sensitivity to motion-induced misregistration. We recently demonstrated feasibility of a novel velocity- selective (VS) MRA approach for cerebral applications at 3T, which is a non-subtractive technique and allows large coverage and slow-flow depiction. Aiming to incorporate favorable aspects of both TOF and ASL MRA methods, we propose numerous technical advances for VS MRA to render 3D arteriography, venography and 4D time-resolved MRA. The purpose of this study is first to further develop these VS cerebral MRA techniques in flow phantoms and healthy subjects (Aim 1), then to evaluate the 3D VS MR arteriography in patients with carotid or intracranial stenosis (Aim 2) and the 3D VS MR venography in patients with cerebral venous sinus thrombosis (Aim 3), and finally to evaluate the 4D time-resolved VS-MRA in patients with AVM or aneurysm (Aim 4). The proposed NCE VS MRA 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 .