Thiel F, Kreiseler D, Seifert F
Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany.
Rev Sci Instrum. 2009 Nov;80(11):114302. doi: 10.1063/1.3238506.
Electromagnetic waves can propagate through the body and are reflected at interfaces between materials with different dielectric properties. Therefore the reason for using ultrawideband (UWB) radar for probing the human body in the frequency range from 100 MHz up to 10 GHz is obvious and suggests an ability to monitor the motion of organs within the human body as well as obtaining images of internal structures. The specific advantages of UWB sensors are high temporal and spatial resolutions, penetration into object, low integral power, and compatibility with established narrowband systems. The sensitivity to ultralow power signals makes them suitable for human medical applications including mobile and continuous noncontact supervision of vital functions. Since no ionizing radiation is used, and due to the ultralow specific absorption rate applied, UWB techniques permit noninvasive sensing with no potential risks. This research aims at the synergetic use of UWB sounding combined with magnetic resonance imaging (MRI) to gain complementary information for improved functional diagnosis and imaging, especially to accelerate and enhance cardiac MRI by applying UWB radar as a noncontact navigator of myocardial contraction. To this end a sound understanding of how myocardial's mechanic is rendered by reflected and postprocessed UWB radar signals must be achieved. Therefore, we have executed the simultaneous acquisition and evaluation of radar signals with signals from a high-resolution electrocardiogram. The noncontact UWB illumination was done from several radiographic standard positions to monitor selected superficial myocardial areas during the cyclic physiological myocardial deformation in three different respiratory states. From our findings we could conclude that UWB radar can serve as a navigator technique for high and ultrahigh field magnetic resonance imaging and can be beneficial preserving the high resolution capability of this imaging modality. Furthermore it can potentially be used to support standard electrocardiography (ECG) analysis by complementary information where sole ECG analysis fails, e.g., electromechanical dissociation.
电磁波能够穿透人体，并在具有不同介电特性的材料界面处发生反射。因此，使用超宽带（UWB）雷达在100 MHz至10 GHz频率范围内探测人体的原因显而易见，这表明其有能力监测人体内部器官的运动以及获取内部结构图像。UWB传感器的具体优势包括高时间和空间分辨率、对物体的穿透性、低积分功率以及与现有窄带系统的兼容性。对超低功率信号的敏感性使其适用于人类医疗应用，包括对生命功能的移动和连续非接触监测。由于不使用电离辐射，且应用的比吸收率超低，UWB技术允许进行无潜在风险的非侵入性传感。本研究旨在协同使用UWB探测与磁共振成像（MRI），以获取互补信息，改善功能诊断和成像，特别是通过应用UWB雷达作为心肌收缩的非接触导航器来加速和增强心脏MRI。为此，必须深入了解反射和后处理的UWB雷达信号如何呈现心肌的力学特性。因此，我们同时采集并评估了雷达信号与高分辨率心电图信号。从几个放射学标准位置进行非接触式UWB照射，以在三种不同呼吸状态下的周期性生理性心肌变形过程中监测选定的浅表心肌区域。从我们的研究结果可以得出结论，UWB雷达可作为高场和超高场磁共振成像的导航技术，有助于保持这种成像方式的高分辨率能力。此外，它还可能通过在单独的心电图分析失败（例如电机械分离）时提供互补信息来支持标准心电图（ECG）分析。
