Laminar Perfusion Imaging

层流灌注成像

• 批准号: 10455051
• 负责人: Danny JJ WANG
• 金额: $ 49.74万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10455051
• 关键词: 3-Dimensional; Adoption; Affect; Algorithms; Anatomy; Animals; Blood flow; Brain; Brain Diseases; Cerebral cortex; Cerebrovascular Circulation; Clinical; Communities; Complex; Data; FDA approved; Functional Magnetic Resonance Imaging; Goals; Human; Image; Imaging technology; Label; MRI Scans; Magnetic Resonance Imaging; Magnetism; Maps; Measurement; Measures; Metabolic; Metabolism; Methods; Noise; Oxygen; Pattern; Perfusion; Physiologic pulse; Pial Veins; Public Health; Research; Resolution; Rest; Sampling; Scheme; Short-Term Memory; Signal Transduction; Site; Specimen; Spin Labels; Surface; System; Techniques; Technology; Time; Tissues; Variant; Water; arterial spin labeling; base; blood flow measurement; blood oxygen level dependent; brain tissue; cerebral blood volume; denoising; health goals; imaging modality; improved; in vivo; innovation; magnetic field; metabolic imaging; neurovascular; new technology; next generation; non-invasive imaging; novel; perfusion imaging; quantitative imaging; reconstruction; relating to nervous system; response; temporal measurement; virtual

PROJECT SUMMARY The goal of this project is to further develop and optimize the next generation arterial spin labeling (ASL) technologies for quantitative mapping of microvascular perfusion at the level of cortical layers and columns on the first FDA approved ultrahigh magnetic (UHF) system, the 7T Terra. Blood oxygen level dependent (BOLD) fMRI is the most widely used non-invasive imaging modality for studying the dynamics of macroscopic brain networks and mesoscopic brain circuits. However, BOLD contrast is susceptible to contaminations of pial veins on the cortical surface that significantly confounds laminar fMRI. Cerebral blood flow (CBF) or microvascular perfusion measured by ASL is a key parameter for in vivo assessment of neurovascular function. The ASL signal is localized close to the site of neural activation and offers the unique capability for quantitative CBF measurements both at rest and during task activation. We pioneered laminar perfusion imaging using 3D inner- volume GRASE (Gradient and Spin Echo) ASL at 7T with a spatial resolution of ~1mm3. However, a sub- millimeter spatial resolution, and ideally at the level of ~0.1mm3 (or ~0.5x0.5x0.5mm3), is required for reliable differentiation of neural activities across cortical layers and columns, as well as for comparison with the state- of-the-art BOLD and CBV fMRI. We will take advantage of a few latest technical breakthroughs in our lab: 1) Cutting-edge ASL pulse sequences with optimized spin labeling strategies for laminar perfusion imaging at 7T; 2) A novel k-t CAIPIRANHA scheme in conjunction with a total-generalized-variation (TGV) regularized algorithm for robust under-sampling patterns and constrained reconstruction; and 3) A novel denoising technique termed k-space weighted image average (KWIA) invented by our group that is able to reduce the thermal noise by 50% and double the signal-to-noise ratio (SNR) of dynamic MRI without significantly affecting the spatial and temporal resolution. We will then apply the advanced ASL methods to precisely measure perfusion, arterial transit time (ATT) and T1 of brain tissue across cortical layers during resting state, as well as to precisely measure task induced perfusion signal changes across cortical layers and columns using sensorimotor stimulation and working memory tasks. As an exploratory aim, we will further develop an innovative pulse sequence for concurrent measurements of T2w BOLD, CBF and CBV contrasts at 7T for mesoscopic imaging of metabolic activities. The developed ASL technologies and research findings will be highly valuable to both basic and clinical neuroscientific research. We will also evaluate the developed next- generation ASL pulse sequences and post-processing algorithms at 3T, and disseminate these technologies to other sites with 3 and/or 7T MR systems to facilitate the widespread adoption of our technologies by the neuroscientific community.

项目摘要 该项目的目的是进一步开发和优化下一代动脉旋转标签（ASL） 在皮层层和柱上的微血管灌注定量映射的技术 第一个FDA批准的超高磁性（UHF）系统，7T Terra。血氧水平依赖（粗体） fMRI是用于研究宏观脑动力学的最广泛使用的非侵入性成像方式 网络和介观脑电路。但是，粗体对比容易受到丘脑污染的影响 在皮质表面上显着混淆了层流fMRI。脑血流（CBF）或微血管 通过ASL测量的灌注是体内评估神经血管功能的关键参数。 ASL 信号位于靠近神经激活部位的位置，并为定量CBF提供了独特的能力 在休息和任务激活期间的测量。我们使用3D内部 - 开创了层流灌注成像 在7T处的体积grase（梯度和自旋回波）ASL，空间分辨率为〜1mm3。但是，一个子 毫米空间分辨率，理想情况下是〜0.1mm3的水平（或〜0.5x0.5x0.5mm3），需要可靠 在皮质层和柱上的神经活动的分化，以及与状态的比较 大胆和CBV fMRI。我们将利用实验室中的一些最新技术突破：1） 具有优化的自旋标记策略的尖端ASL脉冲序列，用于7T处的层流灌注成像； 2）一种新型的K-T Caipiranha方案，结合了总临时变化（TGV）正规化 算法，用于健壮的下采样模式和约束重建； 3）一个新颖的denoing 我们小组发明的技术称为K空间加权图像平均（KWIA），能够减少 热噪声的动态MRI的信号噪声比（SNR）倍增50％，而没有显着影响 空间和时间分辨率。然后，我们将应用高级ASL方法精确测量 在静止状态下，灌注，动脉传输时间（ATT）和脑组织的T1，以及 精确衡量任务引起的灌注信号在皮层层和色谱柱之间的变化 感觉运动刺激和工作记忆任务。作为探索目的，我们将进一步发展 T2W BOLD，CBF和CBV的并发测量的创新脉冲序列在7T处对比度 代谢活性的介观像。发达的ASL技术和研究结果将是 对于基本和临床神经科学研究都非常有价值。我们还将评估发达的下一步 在3T处生成ASL脉冲序列和后处理算法，并将这些技术传播到 其他具有3和/或7T MR系统的站点，以促进我们的技术广泛采用 神经科学社区。