脑起搏器是一种重要的用于神经功能疾病治疗的植入式医疗仪器。随着磁共振成像（Magnetic Resonance Imaging, MRI）技术在临床中的普遍应用，越来越多的脑起搏器患者需要接受MRI扫查。然而，因脑起搏器电路系统与MRI的兼容性问题，患者目前只能在脑起搏器关机的状态下进行MRI扫查。为了使患者更好地完成MRI扫查，并降低脑起搏器关机带来的临床治疗风险，解决脑起搏器开机状态下进行MRI扫查的安全性与可靠性问题，具有重要的研究价值和现实意义。首先，本文分析并确立了脑起搏器植入电路系统与MRI兼容性的关键问题：一是MRI静磁场对开关电感变换器中磁性器件的饱和效应；二是开关电感变换器中的磁性器件引起的力、扭矩和MRI图像伪影问题；三是MRI射频场在脑起搏器导线上引起的感应电压。基于上述结论，本文针对MRI静磁场对开关电感变换器中磁芯电感的饱和效应，研究了MRI静磁场对脑起搏器植入电路系统的影响。采用时域电路分析和Pspice电路仿真的方法，分别从器件电流、输出电压和功耗三方面分析了磁芯电感饱和对开关电感变换器的影响，进而确定了磁芯电感在MRI静磁场中正常工作的边界条件，并通过体外实验证明了该边界条件的正确性。只要开关电感变换器中的磁芯电感满足该边界条件，脑起搏器可实现在MRI静磁场下安全开机。其次，对开关电感变换器中的磁芯电感进行了优化设计，减小由其引起的力、扭矩和伪影问题，以获得更好的MRI兼容性。在电感绕组固定不变的前提下，本文采用回型磁芯结构代替传统的I型磁芯结构，并采用纳米晶磁性材料代替传统的铁氧体。实验结果表明，新型磁芯电感在满足上述边界条件的基础上，磁芯体积比传统电感磁芯体积减小了82%，力减小了54%，伪影减小了48%，为MRI环境下植入电路系统的优化设计提供了解决方案。最后，本文研究了MRI射频场对脑起搏器植入电路系统的影响。为解决多场耦合的测量问题，对MRI射频感应电压的测量方法进行了研究，研制了MRI射频感应电压测量装置。该装置从电路结构和电磁屏蔽等多方面进行了优化设计，实现了MRI下射频感应电压测量的高精度和高灵敏度。基于该装置的实验测量数据，分析了射频感应电压对脑起搏器植入电路系统的影响通路及效应，为MRI射频感应电压对植入电路系统影响的评估，以及采取相应的抑制措施提供理论依据。

Deep brain stimulators are important implantable medical instruments for the treatment of neurological disorders. With the widespread use of Magnetic Resonance Imaging (MRI) in clinical practice, greater number of patients with deep brain stimulator implantations are required to undergo MRI scans. However, these patients must deactivate their stimulators for this examination process, due to the incompatibility of the stimulator circuit system with MRI. To overcome this issue, as well as notable risks, it remains valuable to study the security and reliability issues related to MRI examinations in patients with functional implanted medical devices.In the first part of this study, we analyzed and ascertained three key compatibility issues between the implantable circuit system of the stimulator and the MRI. These included: i. The saturation effect on the magnetic devices of switching inductor convert caused by static magnetic field in MRI; ii. Problems of force, torque and MRI artifacts caused by the magnetic devices of switching inductor converter and iii. The induced voltage in the wire of the stimulator caused by the radio-frequency (RF) field in MRI.Based on the analysed above, analysis, simulation and experiments conducted in this study investigated the effects of the MRI static magnetic field on the implantable circuit of a deep brain stimulator. This was aimed to solve the problem of the saturation effect of the MRI static magnetic field on the core of inductor in the switching inductor converter. By using time-domain circuit analysis and Pspice circuit simulation, the influences of core saturation on the switching inductor converter were analyzed througth device current, output voltage and power consumption respectively. Thereafter, the boundary condition during normal function was determined for the inductor with magnetic core in the MRI static magnetic field, and was validated by vitro experiments. It was concluded that with satisfaction of the boundary condition from the core inductor in the switching inductor converter, the deep brain stimulator could be safely turned on in the MRI static magnetic field.Based on the initial findings, experiments in the second study were used to optimize the core of the inductor in switching inductor converter to reduce the force, torque and aritifacts and to obtain the improved MRI compatibility. Given that the inductor winding is fixed, back core structure was used to replace the traditional type I core. Nanocrystalline magnetic material was also used to replace the traditional ferrite. These experimental results showed that the new core inductor reduced the volume of the core (82%), force (54%) and artifact (48%) based on boundary conditions, whereby the optimal design of the implantable circuit system provides a novel solution for MRI compatibility.In the final set of experiments, the effect of MRI RF field on the implantable circuit of a deep brain stimulator was studied. In order to solve the problem of the multi-field coupling measurement, a method for measuring MRI RF induction voltage was investigated, and a device for measuring MRI RF induced voltage was developed. This device was optimized in aspects of circuit structure and electromagnetic shielding. Furthermore, the novel device provided high precision and high sensitivity of RF induced voltage measurements in MRI. Based on the experimental data using this device, the influence of RF induced voltage on the implantable circuit of a deep brain stimulator was analyzed. The theoretical assessment for the evaluation of MRI RF induced voltage on an implantable circuit system was carried out with the correponding suppression measures.