Lattice Boltzmann method for integrating the Bloch equation in muscle fibers and microvessels

Lattice Boltzmann Method;Bloch Equation in Muscle Fibers and Microvessels;Magnetic Resonance Imaging;Finite Element Method;Ageing and Disease;COMSOL

Tennyson, Caroline ; Georgiadis ; John G.

关键词: Lattice Boltzmann Method;    Bloch Equation in Muscle Fibers and Microvessels;    Magnetic Resonance Imaging;    Finite Element Method;    Ageing and Disease;    COMSOL;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/49391/Caroline_Tennyson.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Reduction in lean body mass and increase in fat mass lead to decline in strength and physical function and are therefore largely associated with aging and obesity. Recent research has demonstrated that Magnetic Resonance Imaging (MRI) can measure the local properties of directional water diffusion and lipid concentration in the human muscle. Strong correlations have also been found between overall fitness and MRI measurements related to the transport of water inside the muscle fibers. In addition to water diffusion within the muscle, MR imaging has been used to obtain measurements of the cerebral blood flow. Blood flow in microvascular vessels plays a vital role in the functional exchange of nutrients essential for healthy development, and toxic waste to be removed from the body, between the blood and tissue. Study of the properties of microvascular flow is important in order to effectively understand the change in metabolic support of brain neurons and glial cells with aging or disease. The two objectives of this research project is to interpret MRI measurements related to the diffusion of water inside the muscle fibers, and to utilize the physics underlying how encoding by MRI characterizes the blood flow within the cerebral microvasculature. This is achieved by simulating the way MRI encodes information and applying these simulations to understand the transport of metabolites within the muscle fiber. The primary focus of this thesis is the development of a Lattice Boltzmann model of a single muscle fiber that can be parallelized in the future to include an ordered or disordered array of myofibrils and lipid domains inside the muscle fiber, and numerically simulate the multiphase transport of water, certain metabolites and calcium ions. The combination of Lattice Boltzmann modeling with data obtained from non-invasive MR imaging techniques provides an insight into muscle physiology and metabolism by exploring the connection between local directional diffusion and the distribution of lipids inside the muscle, which was previously only available from invasive techniques requiring muscle biopsy, or was ostensibly impossible. Using a similar approach as the muscle diffusion modeling, the cerebral microvascular blood flow was studied by inputting simple flow inputs on the model with properties characteristic of the cerebral microvessels, thereby providing an innovative technique to extract intrinsic microvascular parameters in the normal aging brain.