Advanced MRI methods to image vascular physiology with respiratory manipulations

 描述(申请人提供)：脑血管成像在各种脑部疾病的治疗中发挥了重要作用，如颅内狭窄、颈动脉狭窄、中风、小血管疾病、脑肿瘤、创伤性脑损伤、烟雾病和药物成瘾条件。基线检查和压力测试在临床实践中都是常用的，它们提供了互补的信息。然而，一个主要限制是收集所有这些信息需要单独扫描，在某些情况下 案子，分开探视。这一限制增加了患者的负担，并显著增加了护理成本。因此，这个R21项目的目标是开发先进的方法来执行提供多个信息领域的血管生理学的一站式成像。建议的技术使用单次扫描的时间来应用O2和CO2气体吸入任务，这两个任务分别提供基线和血管反应性信息，并跟踪气体推注以获得通过时间信息，以及从同一数据集中提取功能连接网络。二氧化碳和氧气是我们身体代谢途径的重要组成部分，但在脑灌注成像的背景下，它们也具有有趣的血管特性。二氧化碳是一种有效的血管扩张剂，可以用来测量血管的反应性。氧气对血管是惰性的，但它的吸入改变了大胆的磁共振信号，这使得可以估计基线脑血容量(CBV)的指数。此外，使用我们新的呼吸模式，二氧化碳和氧气任务都可以在一次扫描的持续时间内完成。此外，吸入的O2和CO2可以作为血流中的团注，用于测量团注到达峰值时间(TTP)。最后，在气体吸入任务中获得的大胆MRI数据可以用于分析大脑的功能连接网络。因此，我们的中心假设是，单次MRI扫描将同时提供基线CBV、脑血管反应性、到达峰值的时间和静息状态的功能连接。我们将首先在健康对照中进行该技术的开发(在 目的1)，然后对颅内动脉狭窄患者进行验证和初步临床演示(目标2)。影响：对临床实践的影响是，同时需要基线和反应性评估的脑血管患者将能够在10-15分钟的一次访问中完成整个过程(而不是每次90分钟的两次访问)。此外，对常规造影剂过敏的患者将有机会获得替代造影剂(即O2和CO2气体)，以满足他们的血管成像需求。

 DESCRIPTION (provided by applicant): Vascular imaging of the brain has played an important role in the management of a variety of brain disorders, such as intracranial stenosis, carotid artery stenosis, stroke, small vessel diseases, brain tumor, traumatic brain injury, Moyamoya disease, and drug-addictive conditions. Both baseline examinations and stress tests are commonly used in clinical practice and they provide complementary information. However, a major limitation is that collection of all of this information requires separate scans and, in some cases, separate visits. This limitation increases patient burden and significantly escalates the cost of care. Therefore, the goal of this R21 project is to develop advanced methods to perform a "one-stop-shop" imaging of vascular physiology that provides multiple domains of information. The proposed technique uses the time of a single scan to apply both O2 and CO2 gas inhalation tasks, which provide baseline and vascular reactivity information, respectively, and tracks the gas bolus to obtain transit time information, as well as extracting functional connectivity networks from the same dataset. CO2 and O2 are important components of our body's metabolic pathway, but they also have interesting vascular properties in the context of brain perfusion imaging. CO2 is a potent vasodilator and can be used to measure vascular reactivity. O2 is inert to blood vessels but its inhalation changes BOLD MRI signal, which allows the estimation of an index of baseline cerebral blood volume (CBV). Furthermore, with our novel breathing paradigm, both CO2 and O2 tasks can be completed concomitantly with the duration of one scan. Additionally, inhaled O2 and CO2 can serve as boluses in the blood stream for the measurement of bolus time-to-peak (TTP). Finally, BOLD MRI data acquired during gas-inhalation tasks can be used for the analysis of functional connectivity networks of the brain. Therefore, our central hypothesis is that a single MRI scan with the proposed procedure will simultaneously provide baseline CBV, cerebrovascular reactivity, time-to-peak, and resting-state functional connectivity. We will first conduct development of the technique in healthy controls (in Aim 1), then perform validation and initial clinical demonstration in patients with intracranial arterial stenosis (in Aim 2). Impact: The impact on clinical practice is that cerebrovascular patients who require both baseline and reactivity assessment will be able to complete the whole procedure with just one visit of 10-15 minutes (as opposed to two visits of 90 minutes each). Additionally, patients who are allergic to conventional contrast agent will have access to an alternative contrast agent (i.e. O2 and CO2 gases) for their vascular imaging needs.