An in-vivo depth-resolved imaging of developing zebrafish microstructure and microvasculature using swept-source optical coherence tomography angiography

Zebrafish as vertebrate model has applications in the fields of embryology, oncology, toxicology, molecular genetics and drug discovery due to its high homology with the human genome. The zebrafish embryogenesis presents a propitious model for concurrent visualization of developmental stages in vivo owing to transparency and ex-utero development of the embryo. Developments in imaging tools and techniques focus on providing real-time quantitative imaging. The present work demonstrates depth-resolved imaging of developing zebrafish using swept-source optical coherence tomography (SSOCT). The SSOCT system provides an axial resolution of 4.5 mu m and an imaging depth of 3.26 mm. The paper also presents imaging of the developing larval microvasculature using a 1 mu m swept-source optical coherence tomography angiography (ssOCTA). A phase-contrast technique of optical coherence angiography calculates the phase differences between consecutive B-scans taken at single location. This technique detects motion induced by moving scatterers. We have also performed depth-resolved OCT angiography to resolve the minute vasculature better. The SSOCT system can capture the detailed microstructures and microvasculature of model organisms in-vivo.