Cerebral Blood Flow in HIV/AIDS and Drug Abuse Detected by CASL MRI

描述（由申请人提供）：有大量证据表明药物使用/滥用（DA）和HIV/AIDS导致CNS损伤。然而，这些研究中的大多数认为，正是这些因素对中枢神经系统的直接影响导致了认知的改变。这项探索性研究的目的是评估一种不同的机制，即血管功能的改变至少是DA和HIV/AIDS对认知影响的部分介质。如果总体假设是正确的，这意味着许多与DA和HIV/AIDS相关的CNS变化是继发于血管变化的，这可能解释了为什么这些条件对认知之间存在协同效应，并建议治疗和预防DA和HIV/AIDS的认知变化的途径，这些途径通常尚未被利用。为了评估中枢神经系统血管系统的改变至少部分负责DA和HIV/AIDS的认知变化的假设，我们将利用一种新的技术，通过磁共振成像-动脉自旋标记。该技术允许在不使用造影剂或电离辐射的情况下测量和标测局部脑血流量（rCBF）。此外，通过在扫描期间挑战受试者呼吸CO2，可以测量对高碳酸血症的急性血管反应。本探索性研究的目的是使我们能够获得必要的数据，以开展血管完整性、DA、HIV/AIDS与CNS结构和功能完整性之间相关性的更大规模、多中心研究。在使用这些用于测量“急性”（即，高碳酸血症）和“慢性”（即，静息）rCBF作为追踪疾病和研究HAD和相关病症的潜在病理生理学的生物标志物，有必要建立关于该技术的稳定性和有效性的一些基本信息。本研究的目的是评估rCBF在个人与艾滋病毒/艾滋病伴随和不伴随药物滥用。具体而言，我们将确定在24周的研究中rCBF稳定的程度，并使用伴随的O 15-水正电子发射断层扫描（PET）测量RCBF来确定MRI技术的标准有效性。艾滋病毒/艾滋病患者可能有思维困难。吸毒的人也可能有思维困难。艾滋病毒/艾滋病感染者或吸毒者的血液循环（血管）也确实有问题。这可能意味着没有足够的血液进入大脑，或者当大脑需要更多血液时，大脑中的血管没有做出正确的反应。使用一种称为磁共振成像的技术来测量大脑中的血流量是可能的，该技术可以拍摄照片，显示血液在大脑各个部位的流动速度。这项探索性研究的目的是开始使用这项新技术来研究艾滋病毒/艾滋病和药物滥用患者大脑中的血流。我们有兴趣知道，他们的血液循环变化是否可能导致他们思维能力的某些变化。

DESCRIPTION (provided by applicant): There is a host of evidence showing CNS damage from drug use/abuse (DA) and HIV/AIDS. However, the majority of these studies assume that it is the direct effects of these factors on the CNS that result in altered cognition. The purpose of this exploratory study is to evaluate a different mechanism - namely, that alterations in vascular function are at least partial mediators of the effects of DA and HIV/AIDS on cognition. If the overall hypothesis is correct, that means that many of the CNS changes associated with DA and HIV/AIDS are secondary to vascular changes, and this might explain why there are synergistic effects between these conditions on cognition, and would suggest pathways for the treatment and prevention of cognitive changes in DA and HIV/AIDS that have not been typically exploited. In order to evaluate the hypothesis that alterations in CNS vasculature are at least partially responsible for the cognitive changes in DA and HIV/AIDS, we will take advantage of a novel technique available through magnetic resonance imaging - Arterial Spin Labelling. This technique allows for the measurement and mapping of regional cerebral blood flow (rCBF) without the use of contrast agents or ionizing radiation. In addition, by challenging the subject to breathe CO2 during the scan, it is possible to measure the acute vascular response to hypercapnia. The purpose of this exploratory study is to allow us to obtain the data necessary to develop a larger scale, multi-center study of the association between vascular integrity, DA, HIV/AIDS and CNS structural and functional integrity. Before using these state-of-the-art methods for measuring both "acute" (i.e., hypercapnic) and "chronic" (i.e., resting) rCBF as biomarkers for tracking disease and for investigating the underlying pathophysiology of HAD and associated conditions, it is necessary to establish some basic information regarding the stability and validity of the techniques. The purpose of this study is to evaluate rCBF in individuals with HIV/AIDS with and without concomitant drug abuse. Specifically, we will determine the extent to which rCBF is stable over 24 weeks of study, and determine the criterion validity of the MRI technique using concomitant O15 -water positron emission tomography (PET) measures of RCBF. Individuals with HIV/AIDS may have difficulty thinking. Individuals who use drugs may also have difficulty with their thinking. It is also true that people with HIV/AIDS or who use drugs may have problems with their circulation (blood vessels). This could mean that not enough blood is getting to the brain, or that the blood vessels in the brain do not respond correctly when the brain needs more blood. It is possible to measure blood flow in the brain using a technique called magnetic resonance imaging, which can take pictures showing how fast blood is moving through various parts of the brain. The purpose of this exploratory study is to begin to use this new technology to study blood flow in the brains of people with HIV/AIDS and drug abuse. We are interested in knowing whether changes in their circulation may be responsible for some of the changes in their ability to think.