In vitro investigation of pacemaker lead heating induced by magnetic resonance imaging: Role of implant geometry
In vitro investigation of pacemaker lead heating induced by magnetic resonance imaging: Role of implant geometry
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DOI：
10.1002/jmri.21536
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发表时间：
2008-10-01
影响因子：
4.4
通讯作者：
Bassen, Howard I.
中科院分区：
文献类型：
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作者：
Calcagnini, Giovanni;Triventi, Michele;Bassen, Howard I.
目的：为评价植入式起搏器（PMs）的几何形状对磁共振成像（MRI）引起的电极导线发热的影响，材料和方法：采用两种不同的设置进行体外实验，使用荧光探针测量温升。第一个实验包括一个装满盐水凝胶的矩形盒子和一个带有导线的起搏器。将该盒子置于MRI鸟笼线圈中，暴露于正弦64 MHz场，校准的全身比吸收率（WB-SAR）为1 W/kg。最高SAR和温度增加（3000 W/kg. 12 ℃）发生在具有最大面积的植入物构型。第二个实验装置由充满凝胶盐水的人形躯干组成。在该设置中，PM及其电极导线暴露于真实的MRI扫描仪，使用WB-SAR高达2 W/kg的临床序列。结果：我们发现，暴露电极导线长度较长的配置产热较高，右胸PM显示出最高温度和局部SAR（11.9摄氏度，2345 W/kg），而左胸PM加热较少（6.3摄氏度，1362 W/kg）。植入物的几何形状，暴露的导线长度，和铅面积必须考虑在广泛的变化引起的温度增加由MRI.Conclusions：MRI引起的铅尖端加热的量强烈依赖于植入物的几何形状，特别是铅面积，暴露的导线长度，和位置的植入物中的幻影。对于较长的电极导线，发现了临界电极导线头端发热。因此，为了尽量减少MRI诱导的电极导线头端发热，PM电极导线应尽可能短。
Purpose: To evaluate the effect of the geometry of implantable pacemakers (PMs) on lead heating induced by magnetic resonance imaging (MRI).Materials and Methods: In vitro experiments were conducted with two different setups, using fluoroptic probes to measure the temperature increase. The first experiment consisted of a rectangular box filled with a gelled saline and a pacemaker with its leads. This box was exposed in an MRI birdcage coil to a sinusoidal 64-MHz field with a calibrated whole-body specific absorption rate (WB-SAR) of 1 W/kg. The highest SAR and temperature increase (3000 W/kg. 12 degrees C) occurred for the implant configuration having the largest area. The second experimental setup consisted of a human-shaped torso filled with gelled saline. In this setup the PM and its lead were exposed to a real MRI scanner, using clinical sequences with WB-SAR up to 2 W/kg.Results: We found that higher heating occurs for configurations with longer exposed lead lengths and that right chest PMs showed the highest temperature and local SAR (11.9 degrees C, 2345 W/kg), whereas the left chest PMs were less heated (6.3 degrees C, 1362 W/kg). Implant geometry, exposed lead length, and lead area must be considered in the wide variation of temperature increases induced by MRI.Conclusions: The amount of MRI-induced lead tip heating depends strongly on implant geometry, particularly the lead area, exposed lead length, and position of the implant in the phantom. Critical lead tip heating was found for the longer leads. Therefore, to minimize MRI-induced lead tip heating, the PM lead should be as short as possible.