Naehle Claas P, Meyer Carsten, Thomas Daniel, Remerie Susann, Krautmacher Carsten, Litt Harold, Luechinger Roger, Fimmers Rolf, Schild Hans, Sommer Torsten
Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany.
Radiology. 2008 Dec;249(3):991-1001. doi: 10.1148/radiol.2493072195.
To evaluate the safety and feasibility of 3-T magnetic resonance (MR) imaging of the brain in patients with implanted cardiac pacemakers (PMs) by using a transmit-receive head coil.
The study protocol was approved by the institutional review board. Signed informed consent was obtained from all subjects. In vitro testing at 3 T was performed with 32 PMs and 45 PM leads that were evaluated for force and torque (by using a floating platform) and radiofrequency (RF)-related heating by using a transmit-receive head coil (maximum specific absorption rate, 3.2 W/kg). Patient examinations at 3 T were performed in 44 patients with a cardiac PM and a strong clinical need; patients underwent a total of 51 MR examinations of the brain by using a transmit-receive head coil to minimize RF exposure of the PM system. An electrocardiograph and pulse oximetry were used for continuous monitoring during MR imaging. The technical and functional PM status was assessed prior to and immediately after MR imaging and at 3 months thereafter. Serum troponin I level was measured before and 12 hours after imaging to detect myocardial thermal injury. PM reprogramming was performed prior to MR imaging depending on the patient's intrinsic heart rate (< 60 beats per minute, asynchronous pacing; > or = 60 beats per minute, sense-only mode).
For in vitro testing, the maximum translational force was 2150 mN (mean, 374.38 mN +/- 392.75 [standard deviation]), and maximum torque was 17.8 x 10(-3) N x m (mean, [2.29 +/- 4.08] x 10(-3) N x m). The maximum temperature increase was 2.98 degrees C (mean, 0.16 degrees C +/- 0.45). For patient examinations, all MR examinations (51 of 51) were completed safely. There were no significant (P < .05) changes in lead impedance, pacing capture threshold level, or serum troponin I level.
MR imaging of the brain at 3 T in patients with a cardiac PM can be performed safely when dedicated safety precautions (including the use of a transmit-receive head coil) are taken.
通过使用发射-接收头部线圈，评估植入心脏起搏器（PM）的患者进行3-T磁共振（MR）脑成像的安全性和可行性。
本研究方案经机构审查委员会批准。所有受试者均签署了知情同意书。在3 T下对32个PM和45根PM导线进行体外测试，通过使用发射-接收头部线圈（最大比吸收率为3.2 W/kg）评估力和扭矩（使用浮动平台）以及射频（RF）相关加热情况。对44例有心脏PM且有强烈临床需求的患者进行3 T下的患者检查；患者使用发射-接收头部线圈共进行了51次脑部MR检查，以尽量减少PM系统的RF暴露。在MR成像期间使用心电图仪和脉搏血氧仪进行连续监测。在MR成像前、成像后即刻以及此后3个月评估PM的技术和功能状态。在成像前和成像后12小时测量血清肌钙蛋白I水平，以检测心肌热损伤。根据患者的固有心率（<60次/分钟，非同步起搏；≥60次/分钟，仅感知模式）在MR成像前对PM进行重新编程。
对于体外测试，最大平移力为2150 mN（平均值为374.38 mN±392.75[标准差]），最大扭矩为17.8×10⁻³ N·m（平均值为[2.29±4.08]×10⁻³ N·m）。最大温度升高为2.98℃（平均值为0.16℃±0.45）。对于患者检查，所有MR检查（51次检查中的51次）均安全完成。导线阻抗、起搏捕获阈值水平或血清肌钙蛋白I水平均无显著（P<.05）变化。
当采取专门的安全预防措施（包括使用发射-接收头部线圈）时，植入心脏PM的患者在3 T下进行脑部MR成像可以安全进行。
