Bélanger Nzakimuena Charles, Masís Solano Marissé, Marcotte-Collard Rémy, Lesk Mark Richard, Costantino Santiago
Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec, Canada.
Département d'ophtalmologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada.
Invest Ophthalmol Vis Sci. 2025 May 1;66(5):17. doi: 10.1167/iovs.66.5.17.
Amid efforts to understand spaceflight associated neuro-ocular syndrome (SANS), uncovering the role of the choroid in its etiology is challenged by the accuracy of image segmentation. The present study extended deep learning-based choroid quantification from optical coherence tomography (OCT) to the characterization of pulsatile and topological changes in the macular plane and investigated changes in response to prolonged microgravity exposure.
We analyzed OCT macular videos and volumes acquired from astronauts before, during, and after long-duration spaceflight. Deep learning models were fine-tuned for choroid segmentation and combined with further image processing toward vascularity quantification. Statistical analysis was performed to determine changes in time-dependent and spatially averaged variables from preflight baseline.
For 12 astronauts with a mean age of 47 ± 9 years, there were significant increases in choroid thickness and luminal area (LA) averaged over OCT macular video segments. There was also a significant increase in pulsatile LA. For a subgroup of six astronauts for whom inflight imaging was available, choroid volume, luminal volume, and the choroidal vascularity index over the macular region all increased significantly during spaceflight.
The findings suggest that localized choroid pulsatile changes occur following prolonged microgravity exposure. They show that the choroid vessels expand in a manner similar to the choroid layer across the macular region during spaceflight, with a relative increase in the space they occupy. The methods developed provide new tools and avenues for studying and establishing effective countermeasures to risks associated with long-duration spaceflight.
在努力理解航天相关神经眼综合征（SANS）的过程中，图像分割的准确性对揭示脉络膜在其病因学中的作用构成了挑战。本研究将基于深度学习的脉络膜定量从光学相干断层扫描（OCT）扩展到黄斑平面搏动性和拓扑变化的表征，并研究了长期微重力暴露后的变化。
我们分析了从宇航员在长期太空飞行前、飞行中和飞行后获取的OCT黄斑视频和容积。对深度学习模型进行微调以进行脉络膜分割，并结合进一步的图像处理进行血管化定量。进行统计分析以确定与飞行前基线相比随时间变化和空间平均变量的变化。
对于12名平均年龄为47±9岁的宇航员，OCT黄斑视频段平均脉络膜厚度和管腔面积（LA）显著增加。搏动性LA也显著增加。对于有飞行中成像数据的6名宇航员亚组，黄斑区域的脉络膜体积、管腔体积和脉络膜血管化指数在太空飞行期间均显著增加。
研究结果表明，长期微重力暴露后会发生局部脉络膜搏动性变化。结果表明，在太空飞行期间，脉络膜血管以类似于黄斑区域脉络膜层的方式扩张，其占据的空间相对增加。所开发的方法为研究和制定针对长期太空飞行相关风险的有效对策提供了新工具和途径。
