NEW PULSE-ECHO SYSTEM FOR REAL TIME 3D CARDIAC IMAGING

这项提案要求提供资金以建立实时的可行性 一种新型三维编码激励脉冲回波超声的实现 用于心脏成像的成像系统。新的方法是基于 接收到的采样数据向量的离散化线性模型 根据来自区域内所有散射体的回波的相干和 利息(RO1)。模型的离散化得到了一个矩阵 可以使用正则化伪逆算子求逆的运算符。 在简化的(但现实的)条件下，伪逆算子 简化为一个横向滤波器组，每个滤波器组中的每个滤波器组 确定可以同时采集到的图像行数 满足成像系统的实时性要求。除了……之外 非常适合于并行处理的实时实现， 横向滤波器能够从不同的信号中分离出回波 在执行匹配滤波之前的方向。因此，我们的提法 消除了类似编码励磁系统设计的主要缺陷 仅基于匹配滤波。与传统的脉冲回波相比 基于延迟和(DAS)波束形成的成像系统，我们的方法 使系统在绕射之外具有更高的横向分辨率 DAS波束形成算法施加的限制。距离分辨率为 由最优维纳滤波器实现，即由 成像系统和系统的信噪比(SNR)。模拟法 并对上述分辨率特性进行了实验验证 在这份提案中。对比度噪声比的进一步提高 系统的(CNR)可以通过使用单个常规的 接收波束形成器可在所有商用扫描仪中使用。一个传统的 DAS波束形成器将用于合成多个接收波束以 用作空间掩码，以允许来自R01的回声 波束形成器，同时阻止来自其他方向的数据。这是一个 与以前提出的编码励磁系统相比有显著的改进 基于全向接收器，它产生充满伪像的图像 即使在相对高信噪比的情况下也是如此。一个强大的组合 最优(正则化)重构算子和单个 控制进入系统的数据流的常规波束形成器将 从而产生能够实时3D的稳健的图像重建算子 对像人体组织这样的高散射介质的成像。

This proposal requests funding to establish the feasibility of real-time implementation of a novel 3D coded-excitation pulse-echo ultrasonic imaging system for cardiac imaging. The new approach is based on a discretized linear model of the received sampled data vector that results from the coherent sum of echoes from all scatterers in the region of interest (RO1). The discretization of the model leads to a matrix operator which can be inverted using a regularized pseudoinverse operator. Under simplifying (but realistic) conditions, the pseudoinverse operator is reduced to a transversal filter bank with every filter in the bank determines the number of image lines that cn be acquired simultaneously to meet the real-time requirements of the imaging system. In addition to being well-suited for parallel processing real-time implementation, the transversal filters are capable of decoupling echoes from different directions before performing matched filtering. Thus, our formulation eliminates major drawback of similar coded-excitation systems designed based only on matched filtering. Compared to conventional pulse-echo imaging systems based on delay-and-sum (DAS) beamforming, our approach leads to a system with higher lateral resolution beyond the diffraction limit imposed by DAS beamforming algorithms. The range resolution is achieved by an optimal Wiener filter, i.e., determined by the bandwidth of the imaging system and the system signal-to-noise ratio (SNR). Simulation and experimental verification of the above resolution properties are given in this proposal. A further improvement in the contrast-to-noise ratio (CNR) of the system can be obtained from the use of a single conventional receive beamformer available in all commercial scanners. A conventional DAS beamformer will be used for synthesizing multiple receive beams to serve as spatial masks to allow echoes from R01 at the output of the beamformer while blocking data from other directions. This is a significant improvement over previously proposed coded-excitation systems based on an omnidirectional receiver, which produce artifact-ridden images even in relatively high SNR situations. The combination of a powerful optimal (regularized) reconstruction operator and the use of a single conventional beamformer to control the data flow into the system will result in a robust image reconstruction operator capable of real-time 3D imaging of highly scattering media such as the human tissue.