MR PERFUSION IMAGING FOR FUNCTIONAL BRAIN STUDIES

我们提出了开发定量磁共振(MR)方法的建议 脑血流量(CBF)和血容量(CBV)的成像 基于幅度和相位的血液和组织信号的组合。 人脑CBV和CBF定量成像具有重要意义 在评估一些疾病过程中的重要性，特别是 涉及受试者内部和跨受试者的纵向测量。 此外，它也是理解大脑关系的基础 对正常大脑中的大脑新陈代谢起作用。 与正电子发射断层扫描定量方法的比较 (PET)，MR使用团注Gd(Gd)，对比 智能体具有空间分辨率高、信号强度高等潜在优势。 信噪比(SNR)、无电离辐射、高可用性和更低 成本。然而，磁共振方法量化脑血流量和脑血流量的能力 还没有完全实现。而磁化率效应 团注Gd对舒张率变化的影响(DeltaR2或Delta R*2 信号)通常用于MR灌注成像，这些信号很可能 除了组织中的GD浓度外，还取决于其他因素，例如 脑室隔(例如，红细胞压积)。CBV和CBF定量也 要求测量Gd动脉输入功能(AIF)，其中 时间和空间分辨率、信噪比、信号相对于 浓度，以及对大范围剂量和浓度的反应 (剂量动态范围)是关键的。 我们计划将相移(Delta-Phi)信号与 DeltaR2和Deltar*2用于量化CBV和CBF。在模型系统中， Delta-Phi信号是线性的，具有高信噪比和剂量动态范围。作为 首先，我们将从理论上分析这些信号机制，并 在血液和组织中进行实验。在第二个目标中，信号- 浓度关系将通过实验确定在血液和 组织。最后，定量MR CBV和CBF测量的有效性 用不同的信号组合获得的信号将在 具有正常和生理变化的流动的狒狒。

We proposed to develop quantitative magnetic resonance (MR) methods of imaging cerebral blood flow (CBF) and blood volume (CBV) using combinations of magnitude- and phase-based blood and tissue signals. Quantitative CBV and CBF imaging in the human brain is of significant importance in the evaluation of a number of disease processes, especially those involving longitudinal measurements within and across subjects. Also, it is fundamental in understanding the relationship of brain function to brain metabolism in the normal brain. Compared with the quantitative method of positron emission tomography (PET), MR utilizing bolus administration of gadolinium (Gd), contrast agents has potential advantages of high spatial resolution, high signal- to-signal ratio (SNR), no ionizing radiation, high availability, and lower costs. However, the ability of MR methods to quantitate CBF and CBV has not yet been fully realized. While the magnetic susceptibility effect of bolus Gd injection on change in relaxation rate (deltaR2 or delta R*2 signals) is often used for MR perfusion imaging, these signals are likely dependent on other factors in addition to tissue GD concentration, such as compartmentation (e.g., hematocrit). CBV and CBF quantitations also require measurement of the Gd arterial input function (AIF), where temporal and spatial resolution, SNR, signal linearity with respect to concentration, and response over a wide range of doses and concentrations (dose dynamic range) are critical. We plan to utilize phase shift (delta-phi) signals in conjunction with deltaR2 and deltaR*2 to quantitate CBV and CBF. In model systems, the delta-phi signal is linear and has high SNR and dose dynamic range. As the first Aim, these signal mechanisms will be analyzed theoretically and experimentally in blood and tissue. In the second Aim, signal- concentrations relations will be experimentally determined in blood and tissue. Finally, the validity of quantitative MR CBV and CBF measurements obtained with different signal combinations will be tested against PET in baboons with normal and physiologically-altered flow.