IMPROVED UNDERSTANDING OF CARDIAC FLOWS

用于定义心脏流动事件的新方法的发展已经 不断产生重要的新的临床研究领域， 心脏病学从最早的心音描记术发展到 血流动力学，从标准脉冲和连续波多普勒到新的彩色 血流标测技术以及最近的心脏可视化技术 动态和心脏流动的磁共振成像。 相比 流体力学和体外方法表征流动，大多数 临床血流成像方法显得过于简单， 最好的 动态彩色血流图和血流图像， 许多中心目前还不能定量解释， 有一个明确的认识的决定因素，流映射的颜色 多普勒技术或MRI方法。 我们建议发展一个分阶段的系列流动幻影，从 可表征的稳态简单孔口到搏动性心脏血流 具有模拟多个瓣膜病变的模型。 对这些模型的研究 在可重现的流体动力学条件下， 流动可视化技术-测量和表征将是 包括计算机化的定量粒子 跟踪，激光多普勒风速仪，和多流热 标记用于单独跟踪各个流。 一旦 这些模型中的流动特性已被详细记录 因为它涉及层流区域、流动会聚区域、高 速度射流旋流和湍流，这方面的知识将用于指导 这些技术的成像与数字采集、重建 以及重新显示数据、重新计算和新的显示。 这些 调查将产生一个增强的相关流动现象， 心血管系统 对这些事件的了解应该有助于 加速发展所有心脏的定量能力， 能够流动可视化的成像模式。

The development of new methods for defining cardiac flow events have consistently yielded important new fields of investigation for clinical cardiology from the earliest development of phonocardiography to hemodynamics, from standard pulsed and continuous wave Doppler to new color flow mapping techniques and most recently, visualization of cardiac dynamics and cardiac flows by magnetic resonance imaging. When compared to hydrodynamics and in vitro methods for characterizing flow, most of the clinical flow imaging methods appear oversimplified, and semiquantitative at best. The dynamic color flow maps and flow images now being derived in many centers have not been currently interpretable quantitatively, nor is there a clear understanding of the determinants of flow mapping by color Doppler technologies or MRI methods. We propose the development of a staged series of flow phantoms, from characterizable steady-state simple orifices to pulsatile cardiac flow models with simulated multiple valve lesions. The study of these models under reproducible hydrodynamic conditions with highly accurate in vitro techniques of flow visualization-measurement and characterization will be undertaken, including methods of computerized quantitative particle tracing, laser Doppler anemometry, and multiple flow stream thermal labeling for separate tracing of individual streams. Once the characteristics of flow within these models have been documented in detail as it relates to laminar flow regions, flow convergence regions, high velocity jets swirling and turbulence, this knowledge will be used to guide the imaging of those techniques with digital acquisition, reconstruction and redisplay of the data, recomputation and new displays. These investigations will yield an enhanced relevant flow phenomena within the cardiovascular system. The understanding of these events should aid and accelerate the development of quantitative capabilities for all cardiac imaging modalities capable of flow visualization.