Estimation of two dimensional regional wall motion and two dimensional vector flow

评估区域壁面运动的传统方法需要假设壁面运动的方向，如向空腔中心的运动，或连续框架中最近点的运动。然而，实际的壁运动包括心脏旋转或更复杂的运动，这种实际运动可能反映心脏状况。因此，我们尝试使用高帧率超声心动图（60至89帧/秒）跟踪二维壁运动，而不做任何假设，因为在高帧率回声中，两个连续帧之间的心室壁变形预计很小，这使得跟踪图像变得容易。采用二维复合相关方法，对运动的延续性、周期变化和大兴趣区域三个指标进行适当加权。每个指标的权重是通过最小化人类追踪的累积平方误差来确定的。将该方法应用于另一幅图像，并与简单相关法、假设运动方向的常规方法和常规帧率图像进行了比较。这种综合方法是最准确的。该方法应用于临床疾病，检测到的壁面运动客观地揭示了疾病特有的壁面运动。在第二个研究目标中，我们基于连续性方程对传统的室腔彩色多普勒图像进行二维矢量流估计。用b型回波二维流动图像验证了这一结果，并进行了微气泡注入，对三维流动误差进行了估计。这个结果现在正在准备提交。

Conventional methods to evaluate regional wall motion need assumptios on the direction of wall motion such as motion toward the center of cavity, or the nearest points in the successive frame. However, actual wall motion includes cardiac rotation or more complicated motions and this actual motion may reflect cardiac conditions. Therefore we tried to track two dimensional wall motion without assumptions using high frame rate echocardiography (60 to 89 frame/sec) since defprmation of ventricular wall between two successive frames in high frame rate echo is expected to be small and this makes it easy to track images. We applied composite 2D correlation method, which uses appropriately weighted three indices, continuation of motion, cyclic change and large region of interest. The weight of each indices was determined by minimizing the accumulated squared errors from human tracing. We applied this method to another image and compared the result with simple correlation method, conventional methods with assumption on moving direction and conventional frame rate images. This composite method was the most accurate. This methods was applied to clinical diseases and detected wall motion revealed objectively disease specific wall motions. In the second research aim, we estimated two dimensional vector flow from conventional color Doppler image in ventricular cavity based on continuity equation. This result was examined with visualized 2D flow image by B-mode echo, injecting micro bubble and error derived from 3D flow was estimated computer simulation. This result is now in preparation for submission.