Development and validation of quantitative MRI techniques for CNS tissue

CNS 组织定量 MRI 技术的开发和验证

• 批准号: RGPIN-2019-04505
• 负责人: Kozlowski, Piotr
• 金额: $ 2.99万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714564
• 关键词: Development; validation; quantitative; MRI; techniques

Magnetic Resonance Imaging (MRI) is one of the most versatile imaging techniques for studying fundamental properties of tissue. Of particular significance are quantitative MRI techniques that can measure physical parameters, which can provide more accurate and objective way of characterizing tissue properties of interest. A number of quantitative MRI (qMRI) techniques have been successfully applied to study CNS tissue, most notably: diffusion MRI, quantitative T2 MRI, Quantitative Susceptibility Mapping (QSM), and more recently inhomogeneous Magnetization Transfer (ihMT). In the current application we propose to further develop, test and validate these qMRI techniques to allow better characterization of biophysical properties of the rodent CNS tissue. Long term objective of the proposed research programme is the development, validation and application of quantitative MRI techniques to study biophysical properties of CNS tissue in animals. Short term objectives of the proposed research are: 1. To study fundamental characteristics and limitations of inhomogeneous Magnetization Transfer (ihMT) in rodent CNS tissue. We will establish the dependence of ihMT ratio values on the temperature, T1d filtering and orientation with regards to the magnetic field, both in vivo and ex vivo. We will also study the effect of tissue fixation on ihMT measurements by studying the effect of fixation time on the ihMT ratio values. 2. To carry out a combined MWI + ihMT measurements in rat spinal cord. We will optimize a pulse sequence that combines both quantitative T2 and ihMT methods. This will allow measurement of ihMT effect separately on myelin and intra-/extra-axonal water compartments. These measurements will be carried out in normal and injured rat spinal cords both in-vivo and ex-vivo. 3. To compare MWI, QSM, diffusion MRI, and ihMT in their ability to measure myelin content and distinguish between functional myelin and myelin debris. The measurements will be carried in in normal and injured rat spinal cords, both in-vivo and ex-vivo, and the MRI results will be correlated with histology and Transmission Electron Microscopy (TEM). Significance of the proposed research: The proposed programme aims to further expand research capabilities in the area of non-invasive studies of CNS tissue in animals in vivo. Quantitative, non-invasive imaging technology developed throughout this programme will help to broaden our understanding of animal CNS biology and physiology. In addition this programme will provide excellent opportunities for training graduate students and post-doctoral fellows in an interdisciplinary environment.

磁共振成像（MRI）是研究组织基本特性的最通用的成像技术之一。特别重要的是可以测量物理参数的定量MRI技术，其可以提供表征感兴趣的组织特性的更准确和客观的方式。许多定量MRI（qMRI）技术已成功应用于研究CNS组织，最值得注意的是：扩散MRI、定量T2 MRI、定量磁化率映射（QSM）和最近的非均匀磁化转移（ihMT）。在本申请中，我们建议进一步开发、测试和验证这些qMRI技术，以更好地表征啮齿动物CNS组织的生物物理特性。 拟议研究计划的长期目标是开发、验证和应用定量MRI技术，以研究动物中枢神经系统组织的生物物理特性。 拟议研究的短期目标是： 1.目的研究啮齿动物中枢神经系统非均匀磁化传递的基本特征和局限性。 我们将建立ihMT比值对温度、T1 d滤波和磁场方向的依赖性，包括体内和体外。我们还将通过研究固定时间对ihMT比值的影响来研究组织固定对ihMT测量的影响。 2.在大鼠脊髓中进行MWI + ihMT联合测量。 我们将优化结合定量T2和ihMT方法的脉冲序列。这将允许分别测量ihMT对髓磷脂和轴突内/轴突外水隔室的作用。这些测量将在正常和损伤的大鼠脊髓中进行体内和体外测量。 3.比较MWI、QSM、扩散MRI和ihMT测量髓鞘含量并区分功能性髓鞘和髓鞘碎片的能力。 将在正常和损伤的大鼠脊髓中进行体内和体外测量，并且将MRI结果与组织学和透射电子显微镜（TEM）相关联。 拟议研究的意义： 拟议的方案旨在进一步扩大动物体内中枢神经系统组织非侵入性研究领域的研究能力。定量，非侵入性成像技术的发展，整个计划将有助于扩大我们对动物中枢神经系统的生物学和生理学的理解。此外，该方案将提供极好的机会，培养研究生和博士后研究员在一个跨学科的环境。