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Instrumentation and methods for intracardiac catheter tracking: Application of ultrasonic ranging and similarity structure analysis.

机译：心脏内导管追踪的仪器和方法：超声测距和相似结构分析的应用。

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Introduction. Radiofrequency ablation is an effective and potentially curative therapy for a number of well-defined supraventricular arrhythmias. However, the application of ablation techniques in more complex arrhythmias, such as atrial fibrillation and flutter, have been limited by difficulties in creating continuous lines of block via transcatheter ablation lesions. Fluoroscopy is inadequate for determining the real-time, three-dimensional (3-D) positions of intracardiac catheters, and prolonged exposure to ionizing radiation poses a significant health risk for both the patient and medical staff. There is a need to provide, at a minimum, supplemental 3-D catheter position information to assist the physician in navigating the catheter to specific endocardial sites. In the past five years, several 3-D catheter tracking technologies have emerged with the promise of improving intracardiac catheter navigation, and enabling the creation of complex lesion patterns. This dissertation introduces a catheter navigation and visualization method that is based on transit-time ultrasonic ranging and the statistical method of similarity structure analysis.; Methods. Computational methods are developed to reconstruct the relative 3-D positions of multiple catheter-based ultrasonic transducers from intercatheter range data. Electrode positions along the catheters are computed using a parametric cubic spline. A geometric model of multiple intracardiac electrophysiology catheters is generated using a formalin-fixed ovine heart and a 3-D spatial digitizer. The geometric model is used in mathematical simulations to determine how accurately the catheter tracking method can reconstruct an array of catheter transducers and electrodes under controlled conditions. A state-of-the-art ranging system is designed and implemented using a high speed digital signal processor core to perform gain control and matched filter signal detection functions. In vitro tracking of a roving electrophysiology catheter was performed in a water tank under low noise conditions with a stationary frame of reference. A in vivo pilot study is performed to assess the tracking system performance under more rigorous conditions.; Results. The simulation results show that a catheter tip positional accuracy of 2 mm can be achieved if the intertransducer distances are measured to within ±2%. Comparison of the positional accuracy at each transducer and electrode showed a high sensitivity to the spatial distribution of the transducers. This suggests a potential improvement in accuracy with prudent positioning of the reference catheters or use of additional transducers. Reduction in the distance measurement error provides a propagating improvement in the transducer and electrode positional accuracies. The lower distance measurement errors not only improve the coordinate fit from the multidimensional scaling algorithm, but also reduce misalignment errors from the Procrustes similarity transform. In vitro tracking in a water tank using a static frame-of-reference showed a mean absolute distance error of −0.322 ± 0.468 mm, when moving the roving catheter in 20 mm increments. An in vivo pilot study showed promising results; however, additional optimization of the signal detection
机译：简介。射频消融术是许多明确定义的室上性心律失常的有效且可能治愈的疗法。然而，消融技术在更复杂的心律不齐中的应用，如房颤和扑动，受到通过经导管消融病变形成连续的阻塞线的困难而受到限制。荧光检查不足以确定心内导管的实时三维（3-D）位置，并且长时间暴露于电离辐射对患者和医护人员均构成重大健康风险。至少需要提供补充的3-D导管位置信息，以帮助医生将导管导航到特定的心内膜部位。在过去的五年中，出现了几种3-D导管跟踪技术，它们有望改善心内导管的导航，并能够创建复杂的病变模式。本文介绍了一种基于渡越时间超声测距的导管导航和可视化方法以及相似结构分析的统计方法。 方法。开发了计算方法以从导管间距离数据重建多个基于导管的超声换能器的相对3-D位置。沿导管的电极位置使用参数三次样条计算。使用福尔马林固定的羊心脏和3-D空间数字转换器生成多个心内电生理导管的几何模型。在数学模拟中使用几何模型来确定导管跟踪方法在受控条件下可以多么精确地重建一系列导管换能器和电极。使用高速数字信号处理器内核来设计和实现最新的测距系统，以执行增益控制和匹配的滤波器信号检测功能。在低噪音条件下使用固定的参照系在水箱中对流动电生理导管的体外跟踪。进行了体内初步研究，以评估在更严格条件下的跟踪系统性能。 结果。仿真结果表明，如果将换能器间的距离测量为±2％以内，则可以实现2 mm的导管尖端定位精度。在每个换能器和电极处的位置精度的比较显示出对换能器的空间分布的高灵敏度。这表明通过谨慎放置参考导管或使用其他换能器，可能会提高准确性。距离测量误差的减小在换能器和电极位置精度方面提供了广泛的改进。较低的距离测量误差不仅可以改善多维比例缩放算法的坐标拟合，还可以减少Procrustes相似度转换带来的失准误差。当以20 mm的增量移动粗纱导管时，使用静态参照系在水箱中进行的体外跟踪显示平均绝对距离误差为-0.322±0.468 mm。一项 vivo 试点研究显示出令人鼓舞的结果；但是，信号检测的其他优化

著录项

  • 作者

    Meyer, Scott Alan.;

  • 作者单位

    Duke University.;

  • 授予单位 Duke University.;
  • 学科 Engineering Biomedical.
  • 学位 Ph.D.
  • 年度 2000
  • 页码 231 p.
  • 总页数 231
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生物医学工程;
  • 关键词

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