Martin Edward T, Coman James A, Shellock Frank G, Pulling Christopher C, Fair Robert, Jenkins Kim
Oklahoma Heart Institute, Tulsa 74133, USA.
J Am Coll Cardiol. 2004 Apr 7;43(7):1315-24. doi: 10.1016/j.jacc.2003.12.016.
The study was done to determine whether patients with pacemakers could safely undergo magnetic resonance imaging (MRI) at 1.5-Tesla (T).
Because of theoretical risks, it is an absolute contraindication for a patient with a pacemaker to undergo MRI. However, there are times when an MRI is needed to provide valuable clinical information.
Fifty-four patients underwent a total of 62 MRI examinations at 1.5-T. The type of MRI examination was not limited and included cardiac, vascular, and general MRI studies using various whole-body averaged specific absorption rate (SAR) of radiofrequency power. Restrictions were not placed on the type of pacemaker present in the patient. All pacemakers were interrogated immediately before and after MRI scanning, and patients were continuously monitored. Before and after MRI, interrogation was done, and pacing and sensing thresholds, as well as lead impedances, were all measured.
A total of 107 leads and 61 pulse generators were evaluated. No adverse events occurred. Forty (37%) of the leads underwent changes, whereas 10 (9.4%) leads underwent a significant change. Only 2 of the 107 (1.9%) leads required a change in programmed output. Threshold changes were unrelated to cardiac chamber, anatomical location, peak SAR, and time from lead implant to the MRI examination. Electrocardiographic changes and patient symptoms were minor and did not require cessation of MRI.
Safety was demonstrated in this series of patients with pacemakers at 1.5-T.
本研究旨在确定植入起搏器的患者是否能够安全地接受1.5特斯拉（T）的磁共振成像（MRI）检查。
由于存在理论风险，起搏器植入患者接受MRI检查是绝对禁忌。然而，有时需要通过MRI来提供有价值的临床信息。
54例患者在1.5T磁场下共接受了62次MRI检查。MRI检查类型不受限制，包括心脏、血管和全身MRI检查，采用了不同的全身平均射频功率比吸收率（SAR）。对患者所植入起搏器的类型未作限制。在MRI扫描前后均立即对所有起搏器进行问询，并对患者进行持续监测。在MRI检查前后进行问询，并测量起搏和感知阈值以及导线阻抗。
共评估了107根导线和61个脉冲发生器。未发生不良事件。40根（37%）导线出现变化，其中10根（9.4%）导线发生显著变化。107根导线中只有2根（1.9%）需要改变程控输出。阈值变化与心腔、解剖位置、峰值SAR以及导线植入至MRI检查的时间无关。心电图变化和患者症状轻微，无需中断MRI检查。
本系列植入起搏器的患者在1.5T磁场下接受MRI检查显示是安全的。
