安置心脏起搏器患者行核磁共振成像检查的安全性

Feasibility study of magnetic resonance imaging for patients with permanent cardiac pacemakers

目的:探讨安置心脏起搏器(Pacemeker,PM)患者进行1.5德斯拉(T)磁共振成像(MRI)检查的可行性。方法:行MRI的21例PM患者(其中2例为PM依赖性患者)设为A组,进行了头、颈、胸和腹部MRI,采用常规扫描方式,射频能量吸收率(specific absorption rate,SAR)限制<2.2W/kg。在MRI前、后及1个月时测定PM程控功能、起搏阈值、心房感知灵敏度、电极阻抗、脉宽、心电图。检查时全程监护和观察扫描图像质量。B组为对照组20例,不行MRI,1个月时观察相应指标,并行相关统计学分析。结果:A组分别做了31个部位扫描,过程顺利,患者无明显不适,PM程控功能无障碍,脉宽和心房感知灵敏度无变化,MRI后和1个月后起搏阈值和电极电阻有变化但无统计学意义(P>0.05)。B组的起搏阈值和电极电阻1个月时也有变化,但无统计学意义(P>0.05)。两组比较无明显差异(P>0.05)。胸部MRI可见PM周围有干扰现象,但不影响MRI范围外的诊断价值。结论:在一定条件下,PM患者做MRI是可行和安全的。

Objective： To investigate the feasibility of magnetic resonance imaging （MRI） for patients with permanent cardiac pacemakers （PM） at 1.5 Tesla （T）. Methods： The 21 patients with PM （including 2 PM-dependent patients） underwent 1.5T MRI scans of head, neck, chest or abdomen, employing the routine sequences for the examined region, and the specific absorption rate （SAR） was limited to 2.2W/kg for all sequences. The model of PM was not selected. In addition, 20 patients with PM who did not undergo MRI scan were taken as the control group. All devices were interrogated in device procedure parameters pre-, post-, and 1month after MRI, including pacing thresholds, atrial sensing thresholds, lead impedances and pulse width thresholds. Continuous monitoring was performed in procedure of MRI. Results.. Patients in MRI group underwent 31 sites MRI scans at 1. ST. During MRI, no patient reported discomfort, and no episode of adverse was observed. Post-, and 1 month after MRI, no difficulties in telemetry or interrogation were seen, no programming changes were noted, and atrial sensing thresholds and pulse width thresholds were unaltered. Although there were some differences but no significant （P〉0.05） in pacing thresholds and lead impedances post-, and 1 month after MRI in comparison with those of pre- MRI. In control group, the pacing thresholds and lead impedances also changed a little 1 month later, but the changes didn＇t achieve statistical difference （P〉0.05）. There was no statistical difference in changes of device parameters between MRI group and control group （P〉0. 05）. Image artifacts caused by the presence of pacemaker system components, only occurred in the chest scans. But the range of image artifacts were small, and around the pulse generator. Therefore, image quality for diagnoses was not influenced. Conclusion： Under defined conditions, MRI （including the chest scans） in patients with permanent pacemakers can be feasible and safe.