一种基于前向成像模型的光声层析图像重建方法

A photoacoustic tomography image reconstruction method based on forward imaging model

在光声层析成像(photoacoustic tomography,PAT)时,不均匀光通量分布、组织复杂的光学和声学特性以及超声探测器的非理想特性等因素会导致重建图像质量下降。本文考虑不均匀光通量、非定常声速、超声探测器的空间脉冲响应和电脉冲响应、有限角度扫描和稀疏采样等因素的影响,建立了前向成像模型。通过交替优化求解成像模型的逆问题,实现光吸收能量分布图和声速分布图的同时重建。仿真、仿体和在体实验结果表明,与反投影法、时间反演法和短滞后空间相干法相比,该方法重建图像的结构相似度和峰值信噪比可分别提高约83%、56%、22%和80%、68%、58%。由上述结果可知,对非理想成像场景采用该方法重建的图像质量有显著提高。

Aiming at the issue of degraded image quality in photoacoustic tomography(PAT)caused by the inhomogeneous light fluence distribution,complex optical and acoustic properties of biological tissues,and non-ideal properties of ultrasonic detectors,we propose a comprehensive forward imaging model.The model takes into account variables such as the inhomogeneous light fluence,unsteady speed of sound,spatial and electrical impulse responses of ultrasonic transducers,limited-view scanning,and sparse sampling.The inverse problem of the imaging model is solved by alternate optimization,and images representing optical absorption and speed of sound(SoS)distributions are reconstructed simultaneously.The results indicate that the structural similarity of the reconstructed images of the proposed method can be enhanced by about 83%,56%,and 22%,in comparison with back projection,time-reversal,and short-lag spatial coherence techniques,respectively.Additionally,the peak signal-to-noise ratio can be improved by approximately 80%,68%and 58%,respectively.This method considerably enhances the image quality of non-ideal imaging scenarios when compared to traditional techniques.