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

该提案要求提供资金，以确定实时 一种新型三维编码激励脉冲回波超声实现 用于心脏成像的成像系统。 新方法基于 所接收的采样数据向量的离散化线性模型， 从来自区域中的所有散射体的回波的相干总和， 利息（RO1）。 模型的离散化导致矩阵 可以使用正则化的伪逆运算符进行逆运算。 在简化（但现实）条件下，伪逆算子 被简化为一个横向滤波器组， 确定可以同时采集的图像行的数量， 满足成像系统的实时性要求。 除了 非常适合于并行处理实时实现， 横向滤波器能够将来自不同回波的回波去耦 在执行匹配滤波之前的方向。 因此，我们的公式 消除了设计的类似编码励磁系统的主要缺点 仅基于匹配滤波。 与传统的脉冲回波相比 成像系统的基础上延迟和总和（DAS）波束成形，我们的方法 导致系统具有超过衍射的更高的横向分辨率 DAS波束成形算法施加的限制。 距离分辨率为 通过最佳维纳滤波器实现，即，由带宽决定， 成像系统和系统信噪比（SNR）。 仿真 并对上述分辨特性进行了实验验证 在这个提议中。 对比度噪声比的进一步提高 (CNR)可以从使用单个常规的 所有商用扫描仪都有接收波束形成器。 常规 DAS波束形成器将用于合成多个接收波束， 用作空间掩模，以允许来自R01的回波在 波束形成器，同时阻挡来自其他方向的数据。 这是一 与先前提出的编码激励系统相比有显著改进 基于全向接收器，其产生伪影缠身的图像 即使在相对高的SNR情况下。 一个强大的 最佳（正则化）重建算子和使用单个 用于控制进入系统的数据流的传统波束形成器将 导致能够进行实时3D重建的鲁棒图像重建算子 高散射介质如人体组织的成像。

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.