一种用于散射介质中联合波速层析成像与像差校正的角畸变矩阵方法
An angular distortion matrix approach for joint wave-speed tomography and aberration correction in scattering media
- Ecole Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院）
- Institut Langevin, ESPCI Paris, PSL University, CNRS（巴黎高等物理化工大学国立研究中心朗之万研究所）
- Institut Bergonié（贝尔吉尼研究所）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
本文提出基于角畸变矩阵的波速层析与像差校正方法，通过时间反转分析估计相位像差，迭代优化波速，并在超声成像中验证其临床潜力。
中文摘要 AI 辅助
尽管波速是控制波传播的最基本属性之一，但在反射成像中，波速分布很少被准确知晓。其估计依赖于分析入射波和反射波所经历的波畸变；然而，它们的贡献难以与介质反射率区分开来，尤其是在以散斑为主的复杂介质中。假设波速与实际波速之间的失配会导致像差，从而降低反射率图像的质量。然而，这些像差携带着关于底层波速非均匀性的信息。在此，我们展示了一种基于矩阵成像构建的角畸变矩阵，能够解开这些信息，以绘制整个视场内的波速图并校正像差。在每个点上，该矩阵分离了入射波和反射波沿明确传播方向累积的畸变。它揭示了强角相关性，可通过时间反转分析加以利用，以估计局部相位像差，从而为波速层析成像提供可观测量。由此得到的波速图改进了用于矩阵成像的传播模型，之后迭代该过程以细化波速，直到残余像差变得可忽略。使用超声作为概念验证，我们在组织仿体上验证了该方法，并展示了其在体内乳腺和肝脏成像中的临床潜力。声速图显示出与恶性乳腺病变一致的对比度以及健康肝脏中的预期值，而像差校正使临床医生常规解读的反射率图像更加清晰。除了超声之外，该方法自然扩展到任何可实现反射矩阵成像的波模态。
英文摘要
Despite being one of the most fundamental properties governing wave propagation, the wave-speed distribution is rarely known accurately in reflection imaging. Its estimation relies on analyzing wave distortions undergone by the incident and reflected waves; however, their contribution is difficult to disentangle from the medium reflectivity, particularly in complex media dominated by speckle. Mismatches between assumed and actual wave speeds result in aberrations that degrade the quality of reflectivity images. Yet these aberrations carry information about the underlying wave-speed heterogeneities. Here, we show that an angular distortion matrix, built upon matrix imaging, can unscramble this information to map the wave speed and correct aberrations across the entire field of view. At each point, this matrix isolates the distortions accumulated by the incident and reflected waves along well-defined propagation directions. It reveals strong angular correlations that can be exploited through time-reversal analysis to estimate local phase aberrations, providing observables for wave-speed tomography. The resulting map improves the propagation model used for matrix imaging, after which the process is iterated to refine the wave speed until residual aberrations become negligible. Using ultrasound as proof of concept, we validate the approach in a tissue-mimicking phantom and illustrate its clinical potential in vivo for breast and liver imaging. Sound-speed maps show contrast consistent with a malignant breast lesion and expected values in a healthy liver, while aberration correction sharpens reflectivity images routinely interpreted by clinicians. Beyond ultrasound, the approach extends naturally to any wave modality in which reflection-matrix imaging can be implemented.
