APPARATUS FOR CEREBRAL BLOOD FLOW MEASUREMENTS AT 3T

描述(摘自申请者摘要)：脑血流量(CBF) 定义代谢底物的传递速率，是大脑的中枢 新陈代谢。一种无创测量局部脑血流量的方法是 因此对于评估与血管内皮细胞的改变相关的病理很重要 大脑代谢，如颈动脉狭窄、中风和脑肿瘤。 申请人建议开发一种用于局部脑血流和血流灌注的磁共振方法。 在正常受试者和患者中绘制区域图并评估该技术 颈动脉狭窄。ASL脑血流灌注新技术 和在这一探索性发展中提出的灌注区标测 应用程序将建立在他们的初步MR连续动脉旋转的基础上 标签(CASL)工作，提供了第一个能够执行的系统 在3T的人类中存在CASL。三个单独选通的CW射频源的阵列和 可独立调谐的自旋标记线圈将被开发用于放置 在左右颈动脉和两侧椎动脉上。这将会有所改善 MR灌注测量有四种方式：(1)提供磁化 免转移技术，允许采集多片、任意 平面、定量MR灌注图；(2)通过以下方式提高敏感度和覆盖率 用一个小的标记线圈覆盖每条主要动脉，从而使 同时标记后循环和前循环的多线圈CASL方法 在3T。此前，连续ASL方法被限制在1.5T以下 可能不安全的射频功率需求；(3)独立标记每个 主要动脉允许标测每条标记物的灌注范围 动脉。因此，除了测量血液流动的总水平到 处于缺血损伤风险区域，我们将开发一种方法 确定三种主要流体各自输送的区域流动比例 输入大脑的多组动脉。申请者将研究可变性 颈动脉和椎动脉的灌注区并重叠在 正常受试者的分水岭地带。此外，他们还将研究这些 中度(50-70%)单侧颈动脉狭窄患者的各项参数。这 将使他们能够确定血流到给定皮质的百分比 来自三个主要动脉供应的体素提供了一种测量 抵押品流动。这一新颖的信息可能对指导和 治疗后颈动脉狭窄的反应。

DESCRIPTION (Adapted from Applicant's Abstract): Cerebral blood flow (CBF) defines the rate of delivery of metabolic substrates and is central to brain metabolism. A noninvasive method for measuring regional cerebral blood flow is therefore important for assessing pathologies associated with alterations in cerebral metabolism such as carotid artery stenosis, stroke and brain tumors. The applicants proposed to develop a MR method for regional CBF and perfusion territory mapping and assess this technique in normal subjects and patients with carotid artery stenosis. The novel ASL technique for cerebral perfusion and perfusion territory mapping proposed in this exploratory development application will build on their preliminary MR continuous Arterial Spin Labeling (cASL) work which has provided the first system capable of performing cASL in humans at 3T. An array of three separately gated CW RF sources and independently detunable spin-labeling coils will be developed for placement over the left and right carotid and both vertebral arteries. This will improve MR perfusion measurements in four ways: (1) provide a magnetization transfer-free technique allowing the acquisition of multi-slice, arbitrary plane, quantitative MR perfusion maps; (2) improve sensitivity and coverage by covering each of the major arteries with a small labeling coil, thus enabling a multi-coil cASL method that will label both posterior and anterior circulation at 3T. Continuous ASL methods have previously been limited to 1.5T by potentially unsafe RF power demands; (3) independently labeling each of the major arteries to allow the mapping of the perfusion territory of each labeled artery. Thus, in addition to measuring the total level of blood flow to a region at risk for ischemic damage, we will develop a method capable of determining the regional flow fraction delivered by each of the three major sets of arterial inputs to the brain. The applicants will study the variability of the carotid and vertebral arteries' perfusion territories and overlap in watershed zones in normal subjects. In addition, they will study these parameters in patients with moderate (50-70%) unilateral carotid stenosis. This will allow them to determine the percentage of blood flow to a given cortical voxel from each of the three major arterial supplies providing a measure of collateral flow. This novel information could be valuable for guiding and following response to treatment of carotid artery stenosis.