Detection of Spinal Cord Injury during Thoracoabdominal Aortic Aneurysm Surgery Using Multi-channel Superconducting Quantum Interference Device

本项目的主要目的是测试超导量子干涉装置（SQUID），用于检测脊髓传导和预测脊髓缺血。(1)脊髓研究SQUID系统的开发（广岛大学）：使用单通道SQUID检测脊髓作用磁场失败。单通道器件的性能限制是造成这种失败的深刻原因。(2)脊髓缺血模型：对成年犬进行胸主动脉交叉夹持60 min诱导脊髓缺血。2002年4月，我们开始在NTT Docomo多媒体实验室（日本横须贺）使用高性能71通道SQUID进行研究。这种多通道装置的实验结果如下。(3)外周复合神经作用磁场（CAF）测量及其空间分析：成功测量了人体正中、尺神经的CAF。用磁图显示神经传导。(4)磁致神经传导损伤的进一步分析：我们成功地用磁研究记录了正中神经传导的缺血变化。在上臂周围放置气动止血带，诱导前臂缺血20分钟。缺血开始后5min，正中神经CAF振幅显著升高，20min时逐渐降低，几乎完全消失。在缺血早期，磁图评价也显示了特征性的发现。(5)用于脊髓研究的多通道SQUID系统的研制：A)-兔脊髓作用磁场；我们成功地可视化上升脊髓传导仅在腰椎区磁研究。B)-狗的研究；由于传感器灵敏度不够，我们无法记录犬索的磁场。如果解决了这个问题，我们将采用一种缺血方案来测试目前的多通道设备来检测脊髓缺血。少

The main purpose of the current project was to test superconducting quantum interference device (SQUID), for detecting the spinal cord conduction and for predicting spinal cord ischemia. (1) Development of SQUID system for spinal cord study (at Hiroshima University) : Detection of spinal cord action magnetic field using one-channel SQUID failed. The limitation of the performance of the one-channel device was the profound cause of this failure. (2) Spinal cord ischemia model : Ischemia was induced in adult dogs by cross-clamping the thoracic aorta for 60 min.On April, 2002, we started to research using high performance 71-channel SQUID at NTT Docomo Multimedia Laboratories (Yokosuka, Japan). This multi-channel device has given results as follows. (3) Measurement of the peripheral compound nerve action magnetic field (CAF) and its spatial analysis : We succeeded in measuring the CAF of the human median and ulnar nerves. Nerve conduction was visualized by means of magnetography. (4) Magne … More tic analysis of ischemia-induced nerve conduction impairment : We succeeded in recording ischemic- changes of the median nerve conduction with magnetic study. Twenty -minute fore-arm ischemia was induced with the pneumatic tourniquet placing around the upper arm. The amplitude of the CAF of the median nerve significantly increased at 5 min after the initiation of ischemia, and it gradually decreased and almost completely disappeared at 20 min. Magnetographic evaluation also showed characteristic findings during early period of ischemia. (5) Development of multi -channel SQUID system for spinal cord study : A)-Spinal cord action magnetic field in rabbit ; We succeeded in visualization of ascending spinal cord conduction only in the lumbar area with magnetic study. B)-Dog study ; We failed to recording magnetic field of the canine cord because of insufficient sensor sensitivity. If this trouble is solved, we will apply an ischemia protocol for testing the current multi-channel device to detect spinal cord ischemia. Less