Longitudinal in vivo OCT/OCTA of gastric tumor microvasculature via an implantable optical window

Understanding the dynamic evolution of gastric tumor microstructure and microvasculature is essential for elucidating tumorigenesis and disease progression. However, in situ imaging of gastric tumors remains challenging due to limited imaging depth, restricted visualization, and difficulties in longitudinal in vivo monitoring. Here, we present an implantable gastric imaging window in mice that enables high-resolution optical coherence tomography (OCT) and OCT angiography (OCTA) for label-free, longitudinal intravital imaging of gastric cancer development. The window provides excellent optical transparency, allowing simultaneous, repeated visualization of tissue microstructure and microvascular remodeling over time in the same animal. Using this platform, we monitored the spatiotemporal interplay between tumor progression, vascular dynamics, and the tumor microenvironment. Notably, we observed progressive microvascular infiltration from the tumor periphery toward the core, culminating in complete vascularization. Quantitative analyses revealed an initial post-operative suppression of microvasculature, followed by recovery and a rapid increase in vascular density, indicating the establishment of a complex neovascular network at later stages. Together, this implantable gastric window combined with OCT/OCTA offers a powerful tool for investigating gastric cancer pathogenesis and for evaluating tumor progression and prognosis in vivo.