Optical coherence tomography angiography (OCTA) can visualize vasculature structures, but provides limited information about the blood flow speeds. Here, we present a second generation variable interscan time analysis (VISTA) OCTA, which evaluates a quantitative surrogate marker for blood flow speed in vasculature. At the capillary level, spatially compiled OCTA and a simple temporal autocorrelation model, {\rho}({\tau}) = exp(-{\alpha}{\tau}), were used to evaluate a temporal autocorrelation decay constant, {\alpha}, as the blood flow speed marker. A 600 kHz A-scan rate swept-source provides short interscan time OCTA and fine A-scan spacing acquisition, while maintaining multi mm2 field of views for human retinal imaging. We demonstrate the cardiac pulsatility and repeatability of {\alpha} measured with VISTA. We show different {\alpha} for different retinal capillary plexuses in healthy eyes and present representative VISTA OCTA of eyes with diabetic retinopathy.
@article{arxiv.2302.11612,
title = {Retinal blood flow speed quantification at the capillary level using temporal autocorrelation fitting OCTA},
author = {Yunchan Hwang and Jungeun Won and Antonio Yaghy and Hiroyuki Takahashi and Jessica M. Girgis and Kenneth Lam and Siyu Chen and Eric M. Moult and Stefan B. Ploner and Andreas Maier and Nadia K. Waheed and James G. Fujimoto},
journal= {arXiv preprint arXiv:2302.11612},
year = {2023}
}