Ali Rehman, Mitcham Trevor M, Singh Melanie, Doyley Marvin M, Bouchard Richard R, Dahl Jeremy J, Duric Nebojsa
Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA.
Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA.
IEEE Trans Comput Imaging. 2023;9:367-382. doi: 10.1109/tci.2023.3261507. Epub 2023 Mar 28.
Spatial variation in sound speed causes aberration in medical ultrasound imaging. Although our previous work has examined aberration correction in the presence of a spatially varying sound speed, practical implementations were limited to layered media due to the sound speed estimation process involved. Unfortunately, most models of layered media do not capture the lateral variations in sound speed that have the greatest aberrative effect on the image. Building upon a Fourier split-step migration technique from geophysics, this work introduces an iterative sound speed estimation and distributed aberration correction technique that can model and correct for aberrations resulting from laterally varying media. We first characterize our approach in simulations where the scattering in the media is known a-priori. Phantom and in-vivo experiments further demonstrate the capabilities of the iterative correction technique. As a result of the iterative correction scheme, point target resolution improves by up to a factor of 4 and lesion contrast improves by up to 10.0 dB in the phantom experiments presented.
声速的空间变化会导致医学超声成像中的像差。尽管我们之前的工作研究了在存在空间变化声速的情况下的像差校正，但由于所涉及的声速估计过程，实际应用仅限于分层介质。不幸的是，大多数分层介质模型并未捕捉到对图像具有最大像差效应的声速横向变化。基于地球物理学中的傅里叶分步偏移技术，这项工作引入了一种迭代声速估计和分布式像差校正技术，该技术可以对横向变化介质产生的像差进行建模和校正。我们首先在介质散射先验已知的模拟中描述我们的方法。体模和体内实验进一步证明了迭代校正技术的能力。在所展示的体模实验中，由于迭代校正方案，点目标分辨率提高了高达4倍，病变对比度提高了高达10.0 dB。
