Computational Imaging Group for MRI diagnostics and therapy, Center for Image Sciences UMC Utrecht, Utrecht, the Netherlands.
Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Brabant, the Netherlands.
Magn Reson Med. 2021 Nov;86(5):2751-2765. doi: 10.1002/mrm.28840. Epub 2021 May 25.
To propose a single setup using the MRI to both measure and validate the transfer function (TF) of linear implants. Conventionally, the TF of an implant is measured in one bench setup and validated using another.
It has been shown that the TF can be measured using MRI. To validate this measurement, the implant is exposed to different incident electric fields, while the temperature increase at the tip is monitored. For a good validation, the incident electric fields that the implant is exposed to should be orthogonal. We perform a simulation study on six different methods that change the incident electric field. Afterward, a TF measurement and validation study using the best method from the simulations is performed. This is done with fiberoptic temperature probes at 1.5 T for four linear implant structures using the proposed single setup.
The simulation study showed that positioning local transmit coils at different locations along the lead trajectory has a similar validation quality compared with changing the implant trajectory (ie, the conventional validation method). For the validation study that was performed, an R ≥ 0.91 was found for the four investigated leads.
A single setup to both measure and validate the transfer function using local transmit coils has been shown to work. The benefits of using the proposed validation method are that there is only one setup required instead of two and the implant trajectory is not varied; therefore, the relative distance between the leap tip and the temperature probe is constant.
提出一种使用 MRI 同时测量和验证线性植入物传递函数（TF）的单一设置。传统上，植入物的 TF 在一个台架设置中进行测量，并在另一个台架设置中进行验证。
已经表明，TF 可以通过 MRI 进行测量。为了验证这种测量，将植入物暴露于不同的入射电场中，同时监测尖端的温升。为了进行良好的验证，植入物暴露于的入射电场应该是正交的。我们对六种不同的改变入射电场的方法进行了模拟研究。之后，使用模拟中最佳方法进行了 TF 测量和验证研究。这是使用提出的单一设置，在 1.5T 下使用光纤温度探头对四种线性植入物结构进行的。
模拟研究表明，与改变植入物轨迹（即传统验证方法）相比，在导引线轨迹的不同位置定位局部发射线圈具有相似的验证质量。对于进行的验证研究，四个研究的引线均发现 R≥0.91。
已经证明，使用局部发射线圈进行 TF 的单一设置测量和验证是可行的。使用所提出的验证方法的好处是，只需要一个设置而不是两个，并且植入物轨迹不会改变；因此，跃起点和温度探头之间的相对距离保持不变。
