Improving the spatial resolution of ultrasonic imaging using coded excitation

描述（由申请人提供）：拟研究的长期目标是开发一种新技术，该技术将显著提高医学超声成像和定量超声（QUS）成像的诊断能力。介绍了一种新的技术——分辨率增强压缩（REC）技术，该技术可以提高现有超声源的有效带宽，从而提高轴向分辨率，并显著提高回波信噪比（eSNR）。该技术不需要构建新的超声波源，并且可以使传统换能器在带宽方面与cMUT设备竞争。通过提高系统的轴向分辨率和带宽，本方案的创新将大大改善传统超声成像。提高的分辨率将允许更小的结构成像，从而提高诊断能力。此外，eSNR的增加导致超声成像系统的穿透深度更大。最后，增加的带宽可用于进一步提高对比度分辨率（CR）与频率复合技术。同样，大带宽成像系统将大大改进QUS成像技术。更大的带宽导致光谱估计（即散射体大小）的方差更小，这反过来表明，使用QUS成像技术，组织将更容易区分。初步数据表明该方法是可行的，但必须通过一组可量化的指标对图像质量进行彻底测试，以确定REC技术提供的真正临床益处。为了发展超声成像技术并实现这一长期目标，提出了两个具体目标。第一个具体目的是研究使用REC技术来提高常规超声成像的轴向分辨率、eSNR和CR。通过REC技术对传统超声成像的改进将通过几个图像质量指标来量化：eSNR，调制传递函数，通过对比度与噪声比的CR和主瓣旁比。第二个具体目标是量化使用传统脉冲技术和REC技术对散射体特性（QUS）的光谱估计的改进。通过REC技术对QUS成像的改进将通过几个质量指标进行量化：可用带宽、估计方差和估计偏差。将使用REC技术对高对比度和低对比度目标和模拟的组织模拟进行测量，并与使用传统脉冲技术的测量进行比较。将量化聚焦、相位像差和衰减对REC技术性能的影响。

DESCRIPTION (provided by applicant): The long term goal of the proposed research is to develop a new technology that will significantly improve the diagnostic capabilities of medical ultrasonic imaging and quantitative ultrasound (QUS) imaging. A novel technique, the resolution enhancement compression (REC) technique, is introduced that enables existing ultrasonic sources to increase their effective bandwidth, thereby improving axial resolution, and also providing a significant increase to the echo signal-to-noise ratio (eSNR). The technique does not require new ultrasonic sources to be constructed and could allow conventional transducers to compete with cMUT devices in terms of bandwidth. The innovations in this proposal will greatly improve conventional ultrasonic imaging by increasing the axial resolution and bandwidth of the system. The improved resolution will allow smaller structures to be imaged leading to improved diagnostic capabilities. In addition, the increase in eSNR leads to greater depth of penetration for ultrasonic imaging systems. Finally, the increased bandwidth can be used to further improve contrast resolution (CR) with frequency compounding techniques. Similarly, QUS imaging techniques would be greatly improved by larger bandwidth imaging systems. Larger bandwidth leads to smaller variance in spectral estimates (i. e. scatterer size) which in turn suggests that tissues will be more differentiable with QUS imaging techniques. Preliminary data suggests the approach is feasible, but a thorough testing of image quality through a set of quantifiable metrics must be examined to determine the true clinical benefits offered by the REC technique. To develop this technology for ultrasonic imaging and meet this long term goal two specific aims are proposed. The first specific aim is to examine the use of the REC technique to improve axial resolution, eSNR, and CR of conventional ultrasonic imaging. The improvement in conventional ultrasonic imaging through the REC technique will be quantified through several image quality metrics: the eSNR, modulation transfer function, CR through the contrast-to-noise ratio, and mainlobe-sidelobe ratios. The second specific aim is to quantify the improvement in spectral estimates of scatterer properties (QUS) using conventional pulsing techniques and the REC technique. The improvement in QUS imaging through the REC technique will be quantified through several quality metrics: the useable bandwidth, estimate variance, and estimate bias. Measurements on tissue mimicking phantoms with high and low contrast targets and simulations will be conducted using the REC technique and compared with measurements using conventional pulsing techniques. Effects of focusing, phase aberration and attenuation on performance of the REC technique will be quantified.