MR Method for Determining Magnetic Field Correlation

描述(由申请人提供)： 这项研究的主要目标是开发一种新的基于称为磁场相关(MFC)的量的磁共振成像(MRI)对比机制。MFC是一种测量水分子在生物组织中扩散时所经历的局部磁场变化的指标。例如，MFC可以提供有关大脑中铁的微观(细胞规模)分布的信息，这可能有助于研究各种神经退行性病变，包括阿尔茨海默氏症和帕金森氏症，这些疾病与大脑铁异常有关。当与顺磁性造影剂联合使用时，MFC成像也可能有助于肿瘤的评估。虽然MFC与可以用标准MR/技术估计的量有关，例如松弛速率和扩散常数，但目前还没有确定MFC的方法。在MFC图像中观察到的对比度将与标准MR/技术获得的对比度不同，MFC成像可以被视为提供了一种新的对比度机制。研究的第一阶段将是我们提出的MFC成像方法的实施、优化和验证。验证将通过使用两种类型的合成模型(幻影)进行一系列成像实验来完成。模体类型将是水悬浮液，一种是酵母细胞，另一种是聚苯乙烯微球。对于这两种类型，将使用顺磁造影剂来系统地调整磁场不均匀。将在获取的成像数据和MFC成像所依据的理论预测之间进行仔细的比较。对于聚苯乙烯微球悬浮液，测量的MFC可以直接与理论预测值进行比较，而不需要使用拟合参数。第二阶段的研究将在20名正常人身上进行体内MFC成像。对于所有受试者，将获得包含基底节的大脑切片的MFC图像。测量的MFC值将与基于组织学和先前MR/研究的模型预测进行比较。将为受试者池计算MFC值的平均值和标准差。这将为MFC成像在神经疾病中的应用提供基线数据。

DESCRIPTION (provided by applicant): The broad goal of the research is to develop a new magnetic resonance imaging (MRI) contrast mechanism based on a quantity called the magnetic field correlation (MFC). The MFC is a measure of how the local magnetic field experienced by water molecules changes as the molecules diffuse through a biological tissue. The MFC can give, for example, information about the microscopic (cellular scale) distribution of iron in the brain, which may be useful in studying a variety of neurodegenerative pathologies, including Alzheimer's and Parkinson's diseases, that are associated with brain iron abnormalities. MFC imaging, when used in conjunction with a paramagnetic contrast agent, may also aid in evaluating tumors. Although the MFC is related to quantities, such as relaxation rates and diffusion constants that can be estimated with standard MR/techniques, there is currently no established method of determining the MFC. The contrast observed in an MFC image will differ from that obtained with standard MR/techniques, and MFC imaging can be regarded as providing a new contrast mechanism. The first phase of the research will be the implementation, optimization, and validation our proposed MFC imaging method. The validation will be accomplished by performing a series of imaging experiments with two types of synthetic models (phantoms). The phantom types will be aqueous suspensions, one with yeast cells and one with polystyrene microspheres. For both types, a paramagnetic contrast agent will be used to systematically adjust the magnetic field inhomogeneities. A careful comparison will be made between the acquired imaging data and the predictions of the theory upon which MFC imaging is based. For the polystyrene microsphere suspensions, the measured MFC can be compared directly, without the use of fitting parameters, to theoretically predicted values. The second phase of the research will demonstrate in vivo MFC imaging in 20 normal human subjects. For all the subjects, MFC images will be obtained of a brain slice containing the basal ganglia. The measured MFC values will be compared with model predictions based on histology and prior MR/studies. The means and standard deviations of the MFC values will be calculated for the subject pool. This will provide baseline data for the application of MFC imaging to neurological disorders.