Electrical spectral imaging using magnetic resonance methods

生物组织的低频电学特性为细胞提供了敏感和有价值的指示 密度、膜性能、电解质浓度和迁移率以及存在或不存在 疾病，特别是在1千赫和1兆赫之间的频率。对这些特性变化的测量 在这些频率之间提供了组织状态的独特视图。电学性质的综合成像 利用电子光谱学，可以对空间和时间相关的组织进行微妙的检查 在脑癌的诊断和治疗中很重要的特征。不幸的是，相对较少的 组织电学特性的报道就在这个频率范围内，因为它们涉及侵入性，而且通常 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 最近已经开发出了分布。然而，这些方法只能在高频下使用 (&gt；100 MHz)或极低频率(&lt；100赫兹)。例如，扩散张量磁技术 磁共振电阻抗断层成像(DT-mREIT)结合了MR扩散张量和MR相位 在很低的频率下产生全各向异性电导率张量图像的重建。 然而，目前的DT-mREIT技术仅限于10赫兹左右的测量频率。 我们现在建议变换mREIT方法来捕获频率范围从10%到10%的光谱效应 赫兹到500千赫。新技术，多频mREIT(MF-mREIT)将通过计算得到验证 模型，细胞和组织幻影和体内使用的大鼠脑癌模型。的具体焦点。 该项目将测量和表征癌细胞培养和鉴定的低频电特性 大鼠大脑中的肿瘤是从这些细胞生长出来的。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使用的新的电疗法 才能成功治疗脑瘤。该技术将在不同的领域得到进一步的应用，包括 组织对肿瘤治疗场、不可逆电穿孔治疗的反应特征，以及 用于构建规划中使用的精确计算模型的组织特性测量 神经调节疗法。

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.