Phase aberration is a phenomenon caused by heterogeneity of the speed of sound in tissue, in which the actual speed of sound of the tissue is different than the assumed speed of sound used for beamforming. It reduces the quality and resolution of ultrasonic images and impairs clinical diagnostic capabilities. Although phase aberration correction (PAC) methods can reduce these detrimental effects, most practical implementations of PAC methods are based on the near field phase screen model, which have limited ability to represent the true aberration induced by inhomogeneous tissue. Accordingly, we propose a locally adaptive phase aberration correction (LAPAC) method that is applied through the use of synthetic aperture. The method is tested using full-wave simulations of models of human abdominal wall, experiments with tissue aberrators, and in vivo carotid images. LAPAC is compared with conventional phase aberration correction (cPAC) where aberration profiles are computed at a preselected depth and applied to the beamformer’s time delays. For all experiments, LAPAC shows an average of 1 to 2 dB higher contrast than cPAC, and enhancements of 3 to 7 dB with respect to the uncorrected cases. We conclude that LAPAC may be a viable option to enhance ultrasound image quality images even in the presence of clinically relevant aberrating conditions.

中文翻译：

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一种用于合成孔径序列的局部自适应相位像差校正 (LAPAC) 方法

相位畸变是由组织中声速的异质性引起的现象，其中组织的实际声速与用于波束成形的假定声速不同。它会降低超声图像的质量和分辨率，并削弱临床诊断能力。尽管相位像差校正 (PAC) 方法可以减少这些不利影响，但 PAC 方法的大多数实际实施都基于近场相位屏幕模型，其表示由不均匀组织引起的真实像差的能力有限。因此，我们提出了一种通过使用合成孔径应用的局部自适应相位像差校正 (LAPAC) 方法。该方法使用人体腹壁模型的全波模拟、组织畸变器实验、和体内颈动脉图像。LAPAC 与传统的相位像差校正 (cPAC) 进行比较，后者在预选深度计算像差分布并应用于波束形成器的时间延迟。对于所有实验，LAPAC 的对比度平均比 cPAC 高 1 到 2 dB，相对于未校正的情况增强了 3 到 7 dB。我们得出结论，即使存在临床相关的畸变情况，LAPAC 也可能是增强超声图像质量图像的可行选择。相对于未校正的情况，增强了 3 到 7 dB。我们得出结论，即使存在临床相关的畸变情况，LAPAC 也可能是增强超声图像质量图像的可行选择。相对于未校正的情况，增强了 3 到 7 dB。我们得出结论，即使存在临床相关的畸变情况，LAPAC 也可能是增强超声图像质量图像的可行选择。