IEEE Trans Ultrason Ferroelectr Freq Control. 2021 May;68(5):1593-1604. doi: 10.1109/TUFFC.2020.3041634. Epub 2021 Apr 26.
As a molecular imaging modality, photoacoustic (PA) imaging has been in the spotlight because it can provide an optical contrast image of physiological information and a relatively deep imaging depth. However, its sensitivity is limited despite the use of exogenous contrast agents due to the background PA signals generated from nontargeted absorbers, such as blood and boundaries between different biological tissues. In addition, clutter artifacts generated in both in-plane and out-of-plane imaging region degrade the sensitivity of PA imaging. We propose a method to eliminate the nontargeted PA signals. For this study, we used a dual-modal ultrasound (US)-PA contrast agent that is capable of generating both the backscattered US and PA signals in response to the transmitted US and irradiated light, respectively. The US images of the contrast agents are used to construct a masking image that contains the location information about the target site and is applied to the PA image acquired after contrast agent injection. In vitro and in vivo experimental results demonstrated that the masking image constructed using the US images makes it possible to completely remove nontargeted PA signals. The proposed method can be used to enhance the clear visualization of the target area in PA images.
作为一种分子成像模式，光声（PA）成像因其能够提供生理信息的光学对比度图像和相对较深的成像深度而受到关注。然而，由于来自非靶向吸收体（如血液和不同生物组织之间的边界）的背景 PA 信号，其灵敏度受到限制，尽管使用了外源性对比剂。此外，在平面内和平面外成像区域产生的杂波伪影降低了 PA 成像的灵敏度。我们提出了一种消除非靶向 PA 信号的方法。在这项研究中，我们使用了一种双模态超声（US）-PA 对比剂，它能够分别响应传输的 US 和照射光产生反向散射 US 和 PA 信号。对比剂的 US 图像用于构建一个掩模图像，该图像包含目标位置的位置信息，并应用于注射对比剂后获得的 PA 图像。体外和体内实验结果表明，使用 US 图像构建的掩模图像可以完全去除非靶向 PA 信号。所提出的方法可用于增强 PA 图像中目标区域的清晰可视化。
