PDF(Pubmed)
Abstract：
The effect of irradiation during computed tomography (CT) imaging on implantable cardioverter-defibrillators (ICDs) has not been fully evaluated in various settings. The purposes of this study were to evaluate the occurrence of electromagnetic interference (EMI) during CT irradiation in various clinically available ICDs with phantom experiments and to determine the potential risks related to irradiation during CT imaging. Five types of clinically available ICDs from five manufacturers were tested. An ICD was combined with an electrocardiogram (ECG) simulator, mounted in a chest phantom, and subjected to CT imaging. Each ICD was irradiated at the maximal power level (tube voltage, 135 kVp; tube current, 510 mA; rotation time, 1.5 s). EMI was defined as oversensing, ventricular tachycardia/ventricular fibrillation (VT/VF) detection, noise, or shock delivery during CT imaging. For ICDs in which EMI was observed, EMI was then evaluated under 144 different irradiation conditions (tube voltage [four patterns from 80-135 kVp], tube current [six patterns from 50-550 mA], and rotation time [six patterns from 0.35-1.5 s]). Testing was also performed during irradiation at the typical doses in three clinical settings and in two settings with inappropriate irradiation of ICDs due to incorrect setup. Among the five ICDs, a shock was delivered by one ICD manufactured by Medtronic (Minneapolis, MN, USA) due to oversensing during irradiation, which occurred at the maximal power level. No oversensing was observed in other ICDs. In the malfunctioned ICD, oversensing was observed in 134 of 144 irradiation patterns, even at a low power in the ICD. The VF-detection criterion was fulfilled in 20 of 134 tests and was significantly associated with tube voltage, tube current, ration time, and tube voltage × rotation time interaction. Although oversensing was observed in three clinical settings (typical chest CT, CT coronary angiography after coronary artery bypass graft, and dynamic assessment for pleural tumors) and one situation during an incorrect scan range on the chest for head perfusion CT, they were not recognized as tachycardia beats. Oversensing was observed when scans were incorrectly set over the ICD during bolus tracking of contrast-enhanced CT. Maximal power CT imaging induced VT/VF detection and shock delivery in one model of ICD placed in a chest phantom. VT/VF detection was observed when tube voltages were high and irradiation times were longer. Oversensing can occur during inappropriate CT imaging, particularly when slices are positioned over the ICD.
摘要：
计算机断层扫描（CT）成像过程中辐照对植入式心律转复除颤器（ICD）的影响尚未在各种环境中得到充分评估。这项研究的目的是通过体模实验评估各种临床可用的ICD在CT辐照过程中电磁干扰（EMI）的发生，并确定CT成像过程中与辐照相关的潜在风险。测试了来自五个制造商的五种临床可用的ICD。ICD与心电图（ECG）模拟器相结合，安装在胸部幻影中，并接受CT成像。每个ICD都以最大功率水平(管电压，135kVp;管电流,510mA；旋转时间，1.5s)。EMI被定义为过度感应，室性心动过速/室颤(VT/VF)检测,噪音,或CT成像期间的电击输送。对于观察到EMI的ICD，然后在144个不同的辐照条件下评估EMI（管电压[80-135kVp的四种模式]，管电流[从50-550毫安的六个模式]，和旋转时间[0.35-1.5s的六个模式])。在三种临床环境中的典型剂量的照射期间以及由于不正确的设置而不适当地照射ICD的两种环境中也进行了测试。在五个ICD中，Medtronic制造的一个ICD（明尼阿波利斯，MN,美国)由于辐照过程中的过度感知，发生在最大功率水平。在其他ICD中未观察到过度感知。在发生故障的ICD中，在144个辐射模式中的134个中观察到过感测，即使在ICD的低功率。在134项测试中有20项符合VF检测标准，并且与管电压显着相关，管电流,配给时间,和管电压×旋转时间相互作用。尽管在三种临床环境中观察到了过度感知（典型的胸部CT，冠状动脉旁路移植术后的CT冠状动脉造影，以及对胸膜肿瘤的动态评估）和一种情况，在头部灌注CT的胸部扫描范围不正确时，他们没有被识别为心动过速。当在对比增强CT的推注跟踪期间错误地在ICD上设置扫描时，观察到过度感知。在放置在胸部体模中的一个ICD模型中，最大功率CT成像引起的VT/VF检测和电击递送。当管电压高且辐照时间较长时，观察到VT/VF检测。在不适当的CT成像期间可能会发生过度感知，特别是当切片位于ICD上时。
