Jiang Daohuai, Lan Hengrong, Tong Shangqing, Zhang Xianzeng, Gao Fei
Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou 350117, China.
School of Biomedical Engineering, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China.
Photoacoustics. 2025 May 22;44:100735. doi: 10.1016/j.pacs.2025.100735. eCollection 2025 Aug.
Photoacoustic imaging combines the advantages of optical and acoustic imaging, making it a promising tool in biomedical imaging. Photoacoustic tomography (PAT) reconstructs images by solving the inverse problem from detected photoacoustic waves to initial pressure map. The heterogeneous speed of sound (SoS) distribution in biological tissue significantly affects image quality, as uncertain SoS variations can cause image distortions. Previously reported dual-speed-of-sound (dual-SoS) imaging methods effectively address these distortions by accounting for the SoS differences between tissues and the coupling medium. However, these methods require recalculating the distribution parameters of the SoS for each frame during dynamic imaging, which is highly time-consuming and poses a significant challenge for achieving real-time dynamic dual-SoS PAT imaging. To address this issue, we propose a signal-domain dual-SoS correction method for PAT image reconstruction. In this method, two distinct SoS regions are differentiated by recognizing the photoacoustic signal features of the imaging target's contours. The signals are then corrected based on the respective SoS values, enabling signal-domain-based dual-SoS dynamic real-time PAT imaging. The proposed method was validated through numerical simulations and in-vivo experiments of human finger. The results show that, compared to the single-SoS reconstruction method, the proposed approach produces higher-quality images, achieving the resolution error by near 12 times and a 30 % increase in contrast. Furthermore, the method enables dual-SoS dynamic real-time PAT reconstruction at 10 fps, which is 187.22 % faster than existing dual-SoS reconstruction methods, highlighting its feasibility for dynamic PAT imaging of heterogeneous tissues.
光声成像结合了光学成像和声学成像的优点，使其成为生物医学成像中一种很有前景的工具。光声层析成像（PAT）通过解决从检测到的光声波到初始压力图的逆问题来重建图像。生物组织中声速（SoS）分布的不均匀性会显著影响图像质量，因为不确定的SoS变化会导致图像失真。先前报道的双声速（dual-SoS）成像方法通过考虑组织与耦合介质之间的SoS差异，有效地解决了这些失真问题。然而，这些方法在动态成像过程中需要为每一帧重新计算SoS的分布参数，这非常耗时，并且对实现实时动态双SoS PAT成像构成了重大挑战。为了解决这个问题，我们提出了一种用于PAT图像重建的信号域双SoS校正方法。在这种方法中，通过识别成像目标轮廓的光声信号特征来区分两个不同的SoS区域。然后根据各自的SoS值对信号进行校正，实现基于信号域的双SoS动态实时PAT成像。所提出的方法通过数值模拟和人体手指的体内实验得到了验证。结果表明，与单SoS重建方法相比，该方法能够产生更高质量的图像，分辨率误差降低近12倍，对比度提高30%。此外，该方法能够以10帧/秒的速度进行双SoS动态实时PAT重建，比现有的双SoS重建方法快187.22%，突出了其在异质组织动态PAT成像中的可行性。
