Sparse Coding-Enabled Low-Fluence Multi-Parametric Photoacoustic Microscopy.
Sparse Coding-Enabled Low-Fluence Multi-Parametric Photoacoustic Microscopy.
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DOI：
10.1109/tmi.2021.3124124
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发表时间：
2022-04
影响因子：
10.6
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中科院分区：
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多参数光声显微镜（PAM）能够在体内微血管水平上同时成像血红蛋白浓度、血氧和流速，在生物医学中显示出相当大的影响。然而，多参数PAM采集需要密集采样，因此需要高激光脉冲重复率（高达MHz），出于安全考虑，这对可应用的脉冲能量设置了严格限制。高速PAM也有类似的限制，它也使用高脉冲重复率的激光。为了实现高的定量精度，除了良好的结构可视化在低水平的激光能量密度在PAM，我们已经开发了一种新的，稀疏编码为基础的两步去噪技术。在活体脑成像的设置中，我们证明了这种无监督学习方法能够将PAM中的激光通量降低5倍，而不会影响图像质量（结构相似性指数测量或SSIM：>0.92）和定量准确性（误差：<4.9%）。这种基于稀疏编码的方法在保持结构成像质量和定量测量精度的同时，显著放宽了PAM对激光通量的要求，预计将促进多参数PAM和高速PAM的应用和临床转化，由于安全考虑或激光源限制，这些方法具有严格的光子预算。
Uniquely capable of simultaneous imaging of the hemoglobin concentration, blood oxygenation, and flow speed at the microvascular level in vivo, multi-parametric photoacoustic microscopy (PAM) has shown considerable impact in biomedicine. However, the multi-parametric PAM acquisition requires dense sampling and thus a high laser pulse repetition rate (up to MHz), which sets a strict limit on the applicable pulse energy due to safety considerations. A similar limitation is shared by high-speed PAM, which also uses lasers with high pulse repetition rates. To achieve high quantitative accuracy besides good structural visualization at low levels of laser fluence in PAM, we have developed a new, sparse coding-based two-step denoising technique. In the setting of intravital brain imaging, we demonstrated that this unsupervised learning approach enabled the reduction of the laser fluence in PAM by 5 times without compromise of the image quality (structural similarity index measure or SSIM: >0.92) and the quantitative accuracy (errors: <4.9%). Offering a significant relaxation in the requirement of PAM on laser fluence while maintaining the quality of structural imaging and accuracy of quantitative measurements, this sparse coding-based approach is expected to facilitate the application and clinical translation of multi-parametric PAM and high-speed PAM, which have a tight photon budget due to either safety considerations or laser source limitations.