磁共振人体组织电特性断层成像（MR EPT）是新兴高场MR成像技术，其成像机制基于组织在MR射频电磁场中表现出来的电特性，与传统MRI基于组织纵向和横向弛豫时间的成像机制不同。MR EPT能够无创提供活体组织电特性断层图像，活体组织电特性能够反映其生理和病理状态，通常不同组织电特性各异，且组织癌变后电特性改变较大，因此MR EPT技术在肿瘤早期诊断等方面具有重要潜在价值。现有MR EPT技术核心算法需要假设较小成像计算区域内组织电特性梯度为零，而人体活体组织电特性分布客观上不均匀，导致成像结果误差较大。针对现有算法这一原理性缺陷，本课题提出了创新的变电特性参数时域有限差分（FDTD）MR EPT算法理论，新算法不受现有算法假设条件限制，在成像区域全局迭代求解组织电特性断层分布，预实验证实新算法收敛性较好，具可行性。本课题开辟了MR EPT全新技术路线，有望实质性提升MR EPT技术。

The technique of high-field magnetic resonance electrical properties tomography (MR EPT) of human tissues is an emerging MR imaging technique, which can non-invasively provide imaging of electrical properties of tissues at arbitrary tomographic slices in vivo. The mechanism of MR EPT is completely different with the mechanism which underlies the current MRI based on the transversal and longitudinal relaxation time. The electrical properties of tissues characterize the biological and pathological status of tissues, varied with different tissues. Studies have proved that the electrical properties between healthy and malignant tissues are very different. Therefore, MR EPT is a potential technique for the early detection of tumors at clinic. However, the key algorithm of current MR EPT assumes that the gradient of electrical properties in the small local region of interest is zero, conflicting with the fact that the distribution of electrical properties of human tissues is inhomogeneous, resulting in poor imaging quality. Aiming at the existed substantial deficiency of current MR EPT technique, this project proposed a novel MR EPT algorithm named finite difference time domain (FDTD) with adjustable electrical properties. Employing the proposed core equations of the new algorithm, the tomographic distribution of electrical properties were calculated using the FDTD method with adjustable electrical properties, without the unreasonable assumption adopted in the current algorithm. The preliminary experiment proved that the new algorithm exhibits excellent convergence, promising to greatly improve the imaging quality. The proposed novel algorithm is completely different with current method, promising to substantially improve the MR EPT technique. The related research may become a great contribution to the high-field MR imaging technique.