Insights into photoacoustic speckle and applications in tumor characterization
Insights into photoacoustic speckle and applications in tumor characterization
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DOI：
10.1016/j.pacs.2019.02.002
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发表时间：
2019-06-01
期刊：
影响因子：
7.9
通讯作者：
Kolios, Michael C.
中科院分区：
文献类型：
--
作者：
Hysi, Eno;Fadhel, Muhannad N.;Kolios, Michael C.
在超声成像中，充分发展的散斑是由随机分布的散射体反向散射的压力波的时空叠加产生的。散斑外观受成像系统特性(横向和轴向分辨率)以及底层组织结构的随机性质的影响。在这项工作中，我们通过模拟和实验研究了声分辨光声成像中的斑点形成。构建了数值和物理模型，以证明PA散斑以类似于超声散斑和未分辨散射结构的方式携带与未分辨吸收体结构有关的信息。基于肿瘤血管的分形学模型被用来研究来自未分辨圆柱形血管的PA斑点。我们发现散斑特征和PA信号的频率成分可以用来监测平均血管大小的变化，这与肿瘤的生长有关。对小鼠肿瘤的实验验证表明，在声分辨光声成像中，PA斑点可以用来表征未分辨的血管系统。
In ultrasound imaging, fully-developed speckle arises from the spatiotemporal superposition of pressure waves backscattered by randomly distributed scatterers. Speckle appearance is affected by the imaging system characteristics (lateral and axial resolution) and the random-like nature of the underlying tissue structure. In this work, we examine speckle formation in acoustic-resolution photoacoustic (PA) imaging using simulations and experiments. Numerical and physical phantoms were constructed to demonstrate that PA speckle carries information related to unresolved absorber structure in a manner similar to ultrasound speckle and unresolved scattering structures. A fractal-based model of the tumor vasculature was used to study PA speckle from unresolved cylindrical vessels. We show that speckle characteristics and the frequency content of PA signals can be used to monitor changes in average vessel size, linked to tumor growth. Experimental validation on murine tumors demonstrates that PA speckle can be utilized to characterize the unresolved vasculature in acoustic-resolution photoacoustic imaging.