Abstract
Purpose :
Optical coherence tomography angiography (OCT-A) enables depth-resolved, exogenous-contrast free imaging of ophthalmic vasculature. However, OCT-A trades-off imaging speed for field-of-view (FOV) and vessel resolution and, thus, is prone to motion artifacts. Spectrally encoded coherence tomography and reflectometry (SECTR) enables en face spectrally encoded reflectometry (SER) imaging simultaneous with cross-sectional OCT, which provides inherently co-registered FOVs and complementary three-dimensional information about sample motion at high spatiotemporal resolution. Here, we present SECTR angiography (SECTR-A) for motion artifact compensation during in vivo imaging of human retinal vasculature.
Methods :
SECTR imaging was performed using a 400 kHz line-rate buffered 1060 nm Axsun swept-source. SER and OCT data were sampled at 2560x500 pix. (spectral x lateral) with 300 frames-per-volume and 8 repeated frames at each B-scan position. OCT-A was performed on OCT and motion-corrected OCT volumes, where lateral eye motions were estimated using SER registration (Fig. 1).
Results :
We demonstrate in vivo SECTR-A of foveal vessels in a healthy volunteer. Registration of OCT B-scans was performed using en face SER frames to compensate for transverse motion artifacts in the SECTR-A volume (Fig, 1(a)). Retinal vessels, including capillaries and the foveal avascular zone, are clearly visualized.
Conclusions :
SECTR-A enables motion-artifact free depth-resolved visualization of retinal vasculature. Co-registration between SER and OCT frames allows for correction of motion artifacts in post-processing and overcomes fundamental limitations of conventional OCT-A. Potential applications of SECTR-A include multi-volumetric registration for improved vascular contrast, and mosaicking for wide-field angiography.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.