MRI Conditional Actively Tracked Metallic Electrophysiology Catheters and Guidewires With Miniature Tethered Radio-Frequency Traps: Theory, Design, and Validation
MRI Conditional Actively Tracked Metallic Electrophysiology Catheters and Guidewires With Miniature Tethered Radio-Frequency Traps: Theory, Design, and Validation
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DOI：
10.1109/tbme.2019.2941460
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发表时间：
2020-06-01
影响因子：
4.6
通讯作者：
Schmidt, Ehud J.
中科院分区：
文献类型：
--
作者：
Alipour, Akbar;Meyer, Eric S.;Schmidt, Ehud J.
目的：心血管介入装置通常有较长的金属编织或骨干，以帮助操纵和推进。然而，金属基心血管介入装置与磁共振成像（MRI）期间存在的射频（RF）场的电磁耦合可能使该装置在MRI扫描仪中使用不安全。我们的目标是开发MRI条件主动跟踪心血管介入装置，通过充分衰减金属编织/管和内部电缆上的感应电流，使用小型谐振浮动射频陷阱（MBaluns）。方法：设计了mbalun，沿传导心血管装置放置在多个位置，以防止驻波的建立并消散射频引起的能量。mbalun由松散缠绕的螺线管构成，对设备金属主干表面电流和内部电缆共模电流产生的横向磁场敏感。利用电磁仿真对MBalun参数进行优化。优化后，将两种不同的MBalun设计应用于核磁共振主动跟踪的金属导丝和金属编织电生理消融导管。控制装置不使用mbalun。MBalun的性能通过网络分析仪量化电流衰减、电磁比吸收率（SAR）分析、高SAR脉冲序列期间的热测试和mri引导的猪心血管导航进行验证。结果：电磁SAR模拟结果显示，使用六个连续的mbalun，导线尖端的衰减接近20 dB。网络分析仪测试证实类似于17 dB/MBalun表面电流衰减。热测试表明，安装了mbalun的导丝尖端温度降低了5.9摄氏度。由于良好的扭矩和mr跟踪可视性，这两种设备都可以实现快速血管导航。结论：与传统设备相比，MBaluns增加了20%的设备直径，提供了有效的空间手段来防止MRI过程中的加热。意义：MBaluns允许使用长金属部件，这提高了主动磁共振引导介入装置的机械性能。
Objective: Cardiovascular interventional devices typically have long metallic braids or backbones to aid in steerability and pushability. However, electromagnetic coupling of metallic-based cardiovascular interventional devices with the radiofrequency (RF) fields present during Magnetic Resonance Imaging (MRI) can make a device unsafe for use in an MRI scanner. We aimed to develop MRI conditional actively-tracked cardiovascular interventional devices by sufficiently attenuating induced currents on the metallic braid/tube and internal-cabling using miniaturized resonant floating RF traps (MBaluns). Method: MBaluns were designed for placement at multiple locations along a conducting cardiovascular device to prevent the establishment of standing waves and to dissipate RF-induced energy. The MBaluns were constructed with loosely-wound solenoids to be sensitive to transverse magnetic fields created by both surface currents on the device's metallic backbone and common-mode currents on internal cables. Electromagnetic simulations were used to optimize MBalun parameters. Following optimization, two different MBalun designs were applied to MR-actively-tracked metallic guidewires and metallic-braided electrophysiology ablation catheters. Control-devices were constructed without MBaluns. MBalun performance was validated using network-analyzer quantification of current attenuation, electromagnetic Specific-Absorption-Rate (SAR) analysis, thermal tests during high SAR pulse sequences, and MRI-guided cardiovascular navigation in swine. Results: Electromagnetic SAR simulations resulted in approximate to 20 dB attenuation at the tip of the wire using six successive MBaluns. Network-analyzer tests confirmed similar to 17 dB/MBalun surface-current attenuation. Thermal tests indicated temperature decreases of 5.9 degrees C in the MBalun-equipped guidewire tip. Both devices allowed rapid vascular navigation resulting from good torquability and MR-Tracking visibility. Conclusion: MBaluns increased device diameter by 20%, relative to conventional devices, providing a spatially-efficient means to prevent heating during MRI. Significance: MBaluns allow use of long metallic components, which improves mechanical performance in active MR-guided interventional devices.