Acikel Volkan, Silemek Berk, Atalar Ergin
Aselsan, REHIS, Ankara, Turkey.
National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey.
Magn Reson Med. 2020 Jun;83(6):2370-2381. doi: 10.1002/mrm.28089. Epub 2019 Nov 25.
To introduce a prototype active implantable medical device (AIMD) for which the induced radiofrequency currents can be controlled wirelessly.
The modified transmission line method is used to formulate how the lead-case impedance of an AIMD affects the temperature rise around the electrode. A prototype AIMD is designed with the aim of controlling the unwanted temperature rise around its electrode during an MRI examination by altering the impedance between the lead and the case of the implant. MRI experiments were conducted with this prototype implant, which also has a built-in temperature sensor at its electrode. During the experiment, the implant's lead-case impedance was controlled using Bluetooth communication with a remote computer, and the lead tip temperature was recorded.
Ten different lead-case impedance values and their corresponding tip temperature rises were examined during MRI experiments. The experimental results confirmed that the tip temperature rise can be controlled by varying the lead-case impedance wirelessly.
The feedback from the temperature at the AIMD tip, together with variable lead-case impedance, enables control of the safety profile of the AIMD during an MRI examination.
介绍一种原型有源植入式医疗设备（AIMD），其感应射频电流可通过无线方式进行控制。
采用改进的传输线方法来阐述AIMD的导联-外壳阻抗如何影响电极周围的温度升高。设计了一种原型AIMD，目的是通过改变植入物导联与外壳之间的阻抗，在磁共振成像（MRI）检查期间控制其电极周围不必要的温度升高。使用该原型植入物进行了MRI实验，该植入物在其电极处还内置了温度传感器。在实验过程中，通过与远程计算机进行蓝牙通信来控制植入物的导联-外壳阻抗，并记录导联尖端温度。
在MRI实验期间检查了10种不同的导联-外壳阻抗值及其相应的尖端温度升高情况。实验结果证实，可以通过无线改变导联-外壳阻抗来控制尖端温度升高。
AIMD尖端温度的反馈，以及可变的导联-外壳阻抗，能够在MRI检查期间控制AIMD的安全状况。
