[Optical coherence tomography angiography (OCT‑A) in rats].

Purpose: Optical coherence tomography angiography (OCT‑A) allows for the non-invasive, three-dimensional visualization of retinal and chorioidal vascular structures. In this study, this new imaging modality was evaluated in rats.
Methods: In vivo imaging in Dark Agouti rats was performed using confocal scanning laser ophthalmoscopy (cSLO) and OCT‑A (Spectralis prototype, Heidelberg Engineering) after adjusting the length of the reference arm. The OCT‑A en-face images were compared to conventional fluorescein angiography cSLO images. The histological examination allowed for correlation of retinal and chorioidal plexus.
Results: While the diagnostic device was developed for use in humans, OCT‑A and cSLO imaging can be applied in rodents after only minor hardware modifications. High-resolution and contrast-enhanced images enable a depth-selective visualization of the three retinal plexus and the inner and outer chorioidal vascular networks. In comparison to fluorescein angiography (FA), OCT‑A is characterized by higher resolution and more accurate three-dimensional localization of vascular structures, particularly in deep layers. A current limitation includes the relatively small area imaged by OCT‑A.
Discussion: The recently developed OCT‑A imaging technology also allows for three-dimensional detection of retinal and chorioidal vascular changes in vivo without dye injection in rodents. OCT may potentially replace invasive FA for specific questions and will be useful in animal models for research of retinal and chorioidal angiogenic processes physiologically and during pharmacological interventions.