The effect of simulation strategies on prediction of power deposition in the tissue around electronic implants during magnetic resonance imaging.
The effect of simulation strategies on prediction of power deposition in the tissue around electronic implants during magnetic resonance imaging.
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DOI：
10.1088/1361-6560/abac9f
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发表时间：
2020-09-16
影响因子：
3.5
通讯作者：
Golestanirad L
中科院分区：
文献类型：
--
作者：
Nguyen BT;Pilitsis J;Golestanirad L
数值模拟越来越多地用于植入导电医疗植入物（如脑深部电刺激（DBS）器械）的患者的高场磁共振成像（MRI）安全性评估。使用真实的患者模型和植入物几何形状进行数值模拟是首选方法，因为它提供了最准确的结果;然而，在许多情况下，由于计算资源的限制，这种方法是不可行的。重建真实的患者和设备模型以及获得准确的组织电特性的困难迫使研究人员采取折衷方案，要么极度简化植入物结构和几何形状，要么简化身体模型的复杂性。本研究检查了植入DBS植入物的患者在MRI期间人体模型和植入物几何结构的解剖细节变化对特定吸收率（SAR）值预测值的影响。我们使用了完全植入DBS植入物的患者衍生模型，并进行了数值模拟，以计算在1.5T（64 MHz）和3 T（127 MHz）下MRI期间的最大SAR。然后，我们评估了组织介电特性的不确定性、身体模型的复杂性、身体/DBS模型的截断以及DBS电极导线几何形状对SAR的影响。我们的研究结果表明，40%的变化，在一个异质体模型中的个别组织的电导率引起的峰值7%的变化，在64 MHz的最大SAR值，和10.6%的变化，在127 MHz的SAR。电导率范围为0.01 S m−1 → 1 S m−1的均质体模型的SAR预测可涵盖非均质体模型预测的SAR变化的全部范围。在植入式脉冲发生器下方截断身体模型，在1.5T和3 T下分别将预测SAR改变了16%和32%，同时分别节省了250%和148%的计算时间和内存分配。相比之下，DBS电极导线几何结构的变化显著改变了SAR，在64 MHz时高达51%，在127 MHz时高达67%。这些结果表明，如果以过度简化植入物几何结构为代价使用真实身体模型，则简化植入物几何结构引入的误差可能会抵消使用真实身体模型的益处。
Numerical simulations are increasingly employed in safety assessment of high-field magnetic resonance imaging (MRI) in patients with conductive medical implants such as those with deep brain stimulation (DBS) devices. Performing numerical simulations with realistic patient models and implant geometry is the preferred method as it provides the most accurate results; however, in many cases such an approach is infeasible due to limitation of computational resources. The difficulties in reconstructing realistic patient and device models and obtaining accurate electrical properties of tissue have compelled researchers to adopt compromises, either to exceedingly simplify implant structure and geometry, or the complexity of the body model. This study examines the effect of variations in anatomical details of the human body model and implant geometry on predicted values of specific absorption rate (SAR) values during MRI in a patient with a DBS implant. We used a patient-derived model of a fully implanted DBS implant and performed numerical simulations to calculate the maximum SAR during MRI at 1.5T (64 MHz) and 3T (127 MHz). We then assessed the effect of uncertainties in dielectric properties of tissue, complexity of body model, truncation of body/DBS model, and DBS lead geometry on SAR. Our results showed that 40% variation in the conductivity of individual tissues in a heterogeneous body model caused a peak of 7% variation in maximum SAR value at 64 MHz, and 10.6% variation in SAR at 127 MHz. SAR predictions from a homogeneous body model with a conductivity range of 0.01 S m−1 → 1 S m−1 could cover the full range of SAR variations predicted by the heterogeneous body model. Truncation of body model below the implanted pulse generator changed the predicted SAR by 16% at 1.5T and 32% at 3T while saving 250% and 148% in computational time and memory allocation, respectively. In contrast, variation in DBS lead geometry significantly changed the SAR by up to 51% at 64 MHz and 67% at 127 MHz. These results suggest that the error introduced by simplifying the implant’s geometry could negate the benefit of using a realistic body model, should such model be used at the expense of oversimplifying implant geometry.
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影响因子：
3.3
作者：
Golestanirad, Laleh;Kazemivalipour, Ehsan;Kirsch, John
通讯作者：
Kirsch, John
影响因子：
6.7
作者：
Golestanirad, L.;Dlala, E.;Graham, S. J.
通讯作者：
Graham, S. J.
影响因子：
4
作者：
Fujimoto K;Angelone LM;Lucano E;Rajan SS;Iacono MI
通讯作者：
Iacono MI
影响因子：
3.3
作者：
Bhusal, Bhumi;Bhattacharyya, Pallab;Martens, Michael
通讯作者：
Martens, Michael
影响因子：
3.3
作者：
Golestanirad L;Rahsepar AA;Kirsch JE;Suwa K;Collins JC;Angelone LM;Keil B;Passman RS;Bonmassar G;Serano P;Krenz P;DeLap J;Carr JC;Wald LL
通讯作者：
Wald LL