Cano Camilo, Gholampour Amir, van Sambeek Marc, Lopata Richard, Wu Min
Department of Biomedical Engineering, Eindhoven University of Technology, De Rondom 70, Eindhoven, The Netherlands.
Department of Vascular Surgery, Catharina Ziekenhuis Eindhoven, Michelangelolaan 2, The Netherlands.
Photoacoustics. 2024 Dec 9;41:100676. doi: 10.1016/j.pacs.2024.100676. eCollection 2025 Feb.
Photoacoustic imaging (PAI) is a developing image modality that benefits from light-matter interaction and low acoustic attenuation to provide functional information on tissue composition at relatively large depths. Several studies have reported the potential of dichroism-sensitive photoacoustic (DS-PA) imaging to expand PAI capabilities by obtaining morphological information of tissue regarding anisotropy and predominant orientation. However, most of these studies have limited their analysis to superficial scanning of samples, where fluence effects are negligible. Herein, we present a mathematical model for the in-depth analysis of the DS-PA signal of biological samples, focusing on estimating tissue orientation. Our model is validated with a B-scan setup for DS-PA imaging in ex-vivo porcine tendon samples, for which collagen displays optical anisotropy. Results show that for in-depth DS-PA imaging, the accumulative fluence modulation due to dichroism overcomes the effect of absorption dichroism affecting the measured signals; however, this effect can be corrected based on the presented model for determining fiber orientation.
光声成像（PAI）是一种正在发展的成像模态，它受益于光与物质的相互作用以及低声学衰减，能够在相对较大深度提供有关组织成分的功能信息。多项研究报道了二向色性敏感光声（DS-PA）成像通过获取组织各向异性和主要取向的形态信息来扩展PAI功能的潜力。然而，这些研究大多将分析局限于样品的表面扫描，在这种情况下，fluence效应可以忽略不计。在此，我们提出了一个用于深入分析生物样品DS-PA信号的数学模型，重点是估计组织取向。我们的模型通过用于体外猪肌腱样品DS-PA成像的B扫描设置进行了验证，猪肌腱样品中的胶原蛋白具有光学各向异性。结果表明，对于深度DS-PA成像，二向色性引起的累积fluence调制克服了吸收二向色性对测量信号的影响；然而，基于所提出的用于确定纤维取向的模型，可以校正这种影响。
