Evaluation of Vascular Malformation Hemodynamics Using ASL Perfusion MRI

描述（由申请人提供）：动静脉畸形（AVM）和硬脑膜动静脉瘘（AVF）是具有直接动静脉（AV）连接的血管畸形。颅内出血是40-70%患者的主要事件，导致显著的发病率和死亡率。目前的非侵入性成像方法，如MR和CT血管造影是不够的，这些病变的复杂的血管结构和血流动力学的综合评价，包括对脑血流（CBF）的影响。即使是数字减影血管造影术（DSA，金标准）也不能提供准确的血流或分流程度的定量评估。在脑的动脉自旋标记（ASL）灌注MRI中，磁标记的动脉血液水被用作可扩散示踪剂。在初步研究中，人们观察到标记的血液不再作为与未经治疗的AVM相关的血管中的扩散示踪剂，而是作为血管内示踪剂，因为它绕过了毛细血管。其效果是，不仅AVM和引流血管明显显示，而且快速传输标记的测量允许AV分流的潜在量化。本提案的目的是检验以下假设：ASL可用作检测和量化AVM或AVF中AV分流的新方法，同时评价对脑灌注的影响。该提案的第一部分重点关注ASL灌注MRI技术在该环境中的进一步开发和优化。在提案的第二部分，还将在一项初步研究中使用优化的ASL灌注MRI技术对正在接受DSA的疑似AVM或AVF患者进行研究，以评估其准确性。在提案的第三部分中，将进一步分析初步研究中获得的信息，以确定是否可以量化AV分流，是否可以检测到与AVM或AVF相关的CBF变化，以及是否可以在接受手术切除或栓塞的患者中检测到AV分流或CBF变化。公共卫生相关性：动静脉畸形（AVM）是脑中的血管畸形，动脉和静脉之间直接连接，使得血液绕过脑组织。患有AVM的患者可能直到AVM导致脑出血才意识到它，这是多达40-70%的患者的首次表现，并可能导致永久性损伤或死亡。目前的成像方法不足以全面评价这些病变，因此本提案的目标是测试一种称为动脉自旋标记（ASL）灌注MRI的新方法，以改善AVM的检测和评价，并评估对附近脑组织的影响。

DESCRIPTION (provided by applicant): Arteriovenous malformation (AVM) and dural arteriovenous fistula (AVF) are vascular malformations with direct arteriovenous (AV) connections. Intracranial hemorrhage is the presenting event in 40-70% of patients, causing significant morbidity and mortality. Current noninvasive imaging methods like MR and CT angiography are inadequate for comprehensive evaluation of the complex vascular architecture and hemodynamics of these lesions, including effects on cerebral blood flow (CBF). Even digital subtraction angiography (DSA, the gold standard) is not capable of providing accurate quantitative assessment of blood flow or degree of shunt. In arterial spin labeled (ASL) perfusion MRI of the brain, magnetically labeled arterial blood water is used as a diffusible tracer. In preliminary studies, it was observed that labeled blood no longer behaves as a diffusible tracer in vessels associated with untreated AVMs, but as an intravascular tracer since it bypasses the capillaries. The effect is that not only are AVM and draining vessels conspicuously demonstrated, but also that measurement of label with rapid transit allows potential quantification of AV shunt. The goal of this proposal is to test the hypothesis that ASL can be used as a novel method to detect and quantify AV shunting in AVM or AVF, while simultaneously evaluating effects on brain perfusion. The first part of the proposal focuses on further development and optimization of the ASL perfusion MRI technique for use in this setting. In the second part of the proposal, patients with suspected AVM or AVF who are undergoing DSA will also be studied using the optimized ASL perfusion MRI technique in a pilot study to assess its accuracy. In the third part of the proposal, the information obtained in the pilot study will be further analyzed to determine whether AV shunting can be quantified, whether alterations in CBF related to an AVM or AVF can be detected, and whether changes in AV shunt or CBF can be detected in those patients undergoing surgical excision or embolization. PUBLIC HEALTH RELEVANCE: An arteriovenous malformation (AVM) is a vascular malformation in the brain with direct connections between arteries and veins such that blood bypasses brain tissue. A patient with an AVM may not be aware of it until the AVM causes hemorrhage into the brain, which is the first presentation in as many as 40-70% of patients and may lead to permanent injury or death. Current imaging methods are inadequate for comprehensive evaluation of these lesions, so the goal of this proposal is to test a new method called arterial spin labeled (ASL) perfusion MRI to improve detection and evaluation of AVMs as well as to assess effects on nearby brain tissue.