Clinical validation of cardiac strain measures with real-time 4D ultrasound

描述（由申请人提供）：近年来，心脏成像技术取得了巨大进步。特别是，实时三维超声（RT3D或4D）能够在短短几秒钟的成像时间内获得整个心脏周期的完整三维图像，从而吸引了心脏病学家的想象力。这些四维（3D +时间）数据序列包含复杂的心壁运动和时间信息，具有极大地增强心脏临床诊断的潜力。然而，大多数心脏检查中心仍然依赖于二维超声心动图，而四维心脏成像中的时间信息往往被忽视。本提案的目标是利用四维超声所包含的丰富信息。特别地，本提案将侧重于4D心脏成像非常适合的常见问题：直接从4D超声测量应变和心脏扭转。本研究的目的是：(1)量化4D超声光流的位移和应变与植入狗心脏的声压测量结果的误差；(2)验证4D超声光流对健康志愿者（正常心脏）和患病心脏的临床等效结果与基于MRI方法获得的类似应变测量结果的假设；(3)验证四维超声光流在性能上比现有基于二维的应变估计方法具有特定优势的假设。我们设计了一种基于光流的四维超声心肌运动跟踪方法。方向位移、应变和心脏扭转可以根据估计的3D +时间运动场自动导出。在目标1和目标2中，将测量具体的位移、应变和扭转，并与定量评估研究中的“金标准”进行比较。在目标3中，我们将在广泛的临床超声心动图患者数据集中广泛比较4D方法和2D方法在估计应变测量方面的性能。一旦完成，为什么以及何时最好使用4D而不是2D测量的问题将得到定量的回答。

DESCRIPTION (provided by applicant): Technology for imaging the heart has advanced dramatically in recent years. In particular, real-time three-dimensional ultrasound (RT3D or 4D) has captured the imagination of cardiologists with its ability to obtain complete three-dimensional images of the heart over an entire cardiac cycle in just a few seconds of imaging. The complex cardiac wall motion and temporal information contained in these four-dimensional (3D + time) data sequences has the potential to greatly enhance clinical diagnoses of the heart. However, most cardiac examination centers still depend on 2D echocardiography, and the temporal information in the 4D cardiac imaging is often overlooked. The goal of this proposal is to utilize the wealth of information contained in 4D ultrasound. In particular, this proposal will focus on a common problem for which 4D cardiac imaging is ideally suited: measuring strain and cardiac torsion directly from 4D ultrasound. The aims of this proposal are: (1) Quantify errors of displacement and strain from optical flow on 4D ultrasound with respect to results obtained by sonomicrometry implanted in dog hearts; (2) Test the hypothesis that optical flow on 4D ultrasound can have clinically equivalent results on healthy volunteers (normal hearts) and diseased hearts compared to similar measures of strain obtained by MRI based methods; (3) Test the hypothesis that optical flow on 4D ultrasound has specific advantages in terms of performance over existing 2D based methods of strain estimation. The design of our method is based on optical flow to track myocardial motion in 4D ultrasound. Directional displacements and strains and cardiac torsion can be automatically derived from the 3D + time motion field estimated. In aims 1 and 2, specific displacements, strains, and torsion will be measured and compared to "gold standards" in quantitative evaluation studies. In aim 3, we will extensively compare the performance of 4D methods and 2D methods in estimating strain measures across a wide range of clinical echocardiography patient data sets. Once completed, the questions of why and when to best use 4D rather then 2D measures will be answered quantitatively. PUBLIC HEALTH RELEVANCE: The significance of the proposed work is that it will provide a novel and effective 3D strain and torsion measuring tool, allowing clinicians to routinely measure wall motion quantitatively and in real-time. In addition this research will provide cardiologists with improved screening tests for diabetic cardiomyopathy (and dyssynchrony) to help them determine those patients that may require more invasive and costly procedures such as heart catheterization from patients that can be safely spared such tests.