Nolen Stephanie, Li Zhongqiang, Wang Jingyu, El Khatib Mirna, Vinogradov Sergei, Yi Ji
Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21231.
Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD 21231.
bioRxiv. 2025 Jun 1:2025.05.29.656845. doi: 10.1101/2025.05.29.656845.
Oxygen metabolism is important to retinal disease development, but current imaging methods face challenges in resolution, throughput, and depth sectioning to spatially map microvascular oxygen.
To develop a multimodal system capable of simultaneous phosphorescence lifetime imaging scanning laser ophthalmoscopy (PLIM-SLO) and visible light optical coherence tomography (VIS-OCT) to capture capillary-level oxygen partial pressure (pO) and structural volumes in rodents.
C57BL/6 mice were imaged by VIS-OCT with high-definition (10 kHz raster) and Doppler (100 kHz circular) protocols. Phosphorescent probe Oxyphor 2P was retro-orbitally injected to enable intravascular PLIM-SLO imaging (200 μs pixel dwell time), while a tunable lens was used to adjust the focal depth. The extracted phosphorescence lifetimes were used for pO calculation. Simultaneous imaging utilized a shared imaging path and synchronized data collection.
VIS-OCT images revealed detailed anatomy and Doppler shifts, while PLIM-SLO provided capillary pO at multiple depths. A hemoglobin oxygen dissociation curve related retinal arterial pO to systemic oxygen saturation as inhaled oxygen was varied. Registered simultaneous images were captured and pO was empirically adjusted for the combined excitation.
Detailed anatomical structures and capillary pO levels can be simultaneously imaged, providing a useful tool to study oxygen metabolism in rodent disease models.
氧代谢对视网膜疾病的发展很重要，但目前的成像方法在分辨率、通量和深度切片方面面临挑战，难以对微血管氧进行空间映射。
开发一种能够同时进行磷光寿命成像扫描激光眼科检查（PLIM-SLO）和可见光光学相干断层扫描（VIS-OCT）的多模态系统，以获取啮齿动物毛细血管水平的氧分压（pO）和结构体积。
采用高清（10 kHz光栅）和多普勒（100 kHz圆周）协议对C57BL/6小鼠进行VIS-OCT成像。经眶后注射磷光探针Oxyphor 2P以实现血管内PLIM-SLO成像（像素驻留时间200 μs），同时使用可调谐透镜调整焦深。提取的磷光寿命用于计算pO。同步成像利用共享成像路径和同步数据采集。
VIS-OCT图像显示了详细的解剖结构和多普勒频移，而PLIM-SLO提供了多个深度的毛细血管pO。随着吸入氧的变化，血红蛋白氧解离曲线将视网膜动脉pO与全身氧饱和度相关联。采集了配准的同步图像，并根据联合激发对pO进行了经验性调整。
可以同时对详细的解剖结构和毛细血管pO水平进行成像，为研究啮齿动物疾病模型中的氧代谢提供了一个有用的工具。
