Reconfigurable MRI technology for low-SAR imaging of deep brain stimulation at 3T: Application in bilateral leads, fully-implanted systems, and surgically modified lead trajectories
Reconfigurable MRI technology for low-SAR imaging of deep brain stimulation at 3T: Application in bilateral leads, fully-implanted systems, and surgically modified lead trajectories
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DOI：
10.1016/j.neuroimage.2019.05.015
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发表时间：
2019-10-01
期刊：
影响因子：
5.7
通讯作者：
Golestanirad, Laleh
中科院分区：
文献类型：
--
作者：
Kazemivalipour, Ehsan;Keil, Boris;Golestanirad, Laleh
植入脑深部电刺激器械的患者从术后MRI检查中获益很大，但由于与植入物射频致热相关的安全风险，这些患者不易使用MRI。最近，我们引入了一种患者可调节的可重构线圈技术，该技术在9个真实患者模型中以1.5 T进行MRI时，可显著降低单个隔离DBS电极导线尖端的局部SAR。这一贡献将我们的工作扩展到更高的领域，证明了将该技术扩展到3T的可行性，并评估了其在双侧电极导线和完全植入系统患者中的性能。我们根据13例患者的术后CT图像开发了双侧DBS电极导线和完全植入DBS系统的患者衍生模型，并进行了有限元模拟，以计算在3T下使用可重新配置的旋转线圈进行MRI期间电极触点处的SAR放大。与传统的正交体线圈相比，可重新配置的线圈系统使单侧电极导线的SAR平均降低了83%，使双侧电极导线的SAR平均降低了59%。在完全植入双侧DBS系统的患者中，植入电极导线轨迹的简单手术修改被证明可将旋转线圈的SAR降低效率提高至>90%。在典型的脑部检查过程中，对电极触点周围的温升进行热分析，结果表明，使用旋转线圈可使温升降低15倍，在相同的翻转角下，组织中的温升为10 ℃。
Patients with deep brain stimulation devices highly benefit from postoperative MRI exams, however MRI is not readily accessible to these patients due to safety risks associated with RF heating of the implants. Recently we introduced a patient-adjustable reconfigurable coil technology that substantially reduced local SAR at tips of single isolated DBS leads during MRI at 1.5 T in 9 realistic patient models. This contribution extends our work to higher fields by demonstrating the feasibility of scaling the technology to 3T and assessing its performance in patients with bilateral leads as well as fully implanted systems. We developed patient-derived models of bilateral DBS leads and fully implanted DBS systems from postoperative CT images of 13 patients and performed finite element simulations to calculate SAR amplification at electrode contacts during MRI with a reconfigurable rotating coil at 3T. Compared to a conventional quadrature body coil, the reconfigurable coil system reduced the SAR on average by 83% for unilateral leads and by 59% for bilateral leads. A simple surgical modification in trajectory of implanted leads was demonstrated to increase the SAR reduction efficiency of the rotating coil to >90% in a patient with a fully implanted bilateral DBS system. Thermal analysis of temperature-rise around electrode contacts during typical brain exams showed a 15-fold heating reduction using the rotating coil, generating 10 degrees C temperature rise in the tissue for the same flip angle.