Electrical spectral imaging using magnetic resonance methods

生物组织的低频电特性为细胞的功能提供了灵敏而有价值的指示 密度、膜性质、电解质浓度和迁移率以及存在或不存在 疾病，特别是在1 kHz和1 MHz之间的频率。测量这些特性的变化 在这些频率之间提供组织状态的独特视图。电特性成像，组合 与电子光谱学，将允许微妙的检查空间和时间依赖的组织 这些特征在脑癌的诊断和治疗中是重要的。不幸的是， 组织电特性的报告都在这个频率范围内，因为它们涉及侵入性， 容易出错的程序。 几种基于磁共振成像（MRI）的非侵入性电特性成像方法 最近开发了一些发行版。然而，这些方法只能在高频下使用 （>100 MHz）或非常低的频率（<100 Hz）。例如，扩散张量磁 共振电阻抗断层成像（DT-MREIT）结合了MR扩散张量和MR相位 图像以在非常低的频率下产生完全各向异性电导率张量图像的重建。 然而，目前的DT-MREIT技术被限制在10 Hz左右的测量频率。 我们现在提出变换MREIT方法来捕获从10 Hz至500 kHz。新技术，多频MREIT（MF-MREIT）将使用计算验证 模型、细胞和组织模型和体内使用脑癌大鼠模型。的具体重点 该项目将测量和表征癌细胞培养物的低频电特性， 这些细胞在老鼠大脑中长出的肿瘤。预计这些测量将导致更好的 了解肿瘤的性质，并帮助规划越来越多地使用的新的电疗法 来成功治疗脑瘤该技术将在不同领域得到进一步应用，包括 表征对肿瘤治疗场的组织反应，不可逆电穿孔治疗，以及 测量组织特性以构建用于规划的精确计算模型 神经调节治疗。

The low-frequency electrical properties of biological tissue provide sensitive and valuable indications of cell density, membrane properties, electrolyte concentrations and mobilities and the presence or absence of disease, particularly at frequencies between 1 kHz and 1 MHz. Measurements of variations in these properties between these frequencies provide a unique view of tissue state. Imaging of electrical properties, combined with electrical spectroscopy, would allow subtle examination of both spatial and time-dependent tissue characteristics that are important in the diagnosis and therapy of brain cancers. Unfortunately, relatively few reports of tissue electrical properties are in this frequency range, because they involve invasive and often error-prone procedures. Several Magnetic Resonance Imaging (MRI)-based, non-invasive methods of imaging electrical property distributions have recently been developed. However, these methods can only be used at high frequencies (>100 MHz) or very low frequencies (<100 Hz). For example, the technique of Diffusion Tensor Magnetic Resonance Electrical Impedance Tomography (DT-MREIT) combines MR diffusion tensor and MR phase images to produce reconstruction of full anisotropic conductivity tensor images at very low frequencies. However, present DT-MREIT techniques are restricted to measurement frequencies of around 10 Hz. We now propose transforming MREIT methods to capture spectral effects over the frequency range from 10 Hz to 500 kHz. The new technique, multifrequency MREIT (MF-MREIT) will be validated using computational models, cell and tissue phantoms and in-vivo using a rat model of brain cancer. The specific focus of the project will be measuring and characterizing low-frequency electrical properties of cancer cell cultures and tumors grown from these cells in rat brains. It is anticipated that these measurements will lead to better understanding of tumor properties and aid in planning new electrical therapies that are increasingly being used to successfully treat brain tumors. The technique will have further application in diverse areas, including characterization of tissue responses to tumor treating fields, irreversible electroporation therapy, and measurement of tissue properties for construction of accurate computational models used in planning neuromodulation treatments.