Parallel transmission to reduce absorbed power around deep brain stimulation devices in MRI: Impact of number and arrangement of transmit channels
Parallel transmission to reduce absorbed power around deep brain stimulation devices in MRI: Impact of number and arrangement of transmit channels
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DOI：
10.1002/mrm.27905
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发表时间：
2019-08-07
影响因子：
3.3
通讯作者：
Wald, Lawrence L.
中科院分区：
文献类型：
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作者：
Guerin, Bastien;Angelone, Leonardo M.;Wald, Lawrence L.
目的评估并行传输（pTx）线圈降低植入脑深部电刺激（DBS）器械患者电极周围吸收功率（APAE）的平均值和方差性能。方法我们模拟了4个pTx线圈（8和16通道，头部和体线圈）和一个鸟笼体线圈。我们使用APAE表征了射频安全风险，APAE是电极头端周围小圆柱形脑组织中沉积功率（单位：瓦特）的积分。我们通过模拟5个真实DBS患者模型（包括完整DBS植入物长度、颅外环和植入式脉冲发生器）评估了APAE均值和方差。结果对于所有患者模型，与鸟笼线圈相比，具有8（16）个通道的PTx线圈能够将APAE平均降低> 18倍（> 169倍），在翻转角均匀性或全局比吸收率（SAR）方面没有成本。此外，局部pTx线圈的性能明显优于体阵列。结论PTx是DBS患者在进行MRI时射频发热问题的一种可能解决方案，但APAE的患者间变异性较大，表明可能需要对患者进行特定的安全性监测。
Purpose To assess the mean and variance performance of parallel transmission (pTx) coils for reduction of the absorbed power around electrodes (APAE) in patients implanted with deep brain stimulation (DBS) devices. Methods We simulated 4 pTx coils (8 and 16 channels, head and body coils) and a birdcage body coil. We characterized the RF safety risk using the APAE, which is the integral of the deposited power (in Watts) in a small cylindrical volume of brain tissue surrounding the electrode tips. We assessed the APAE mean and variance by simulation of 5 realistic DBS patient models that include the full DBS implant length, extracranial loops, and implanted pulse generator. Results PTx coils with 8 (16) channels were able to reduce the APAE by >18x (>169x) compared to the birdcage coil in average for all patient models, at no cost in term of flip angle uniformity or global specific absorption rate (SAR). Moreover, local pTx coils performed significantly better than body arrays. Conclusion PTx is a possible solution to the problem of RF heating of DBS patients when performing MRI, but the large interpatient variability of the APAE indicates that patient-specific safety monitoring may be needed.