Faculty Collaboration Database

Optical Coherence Tomography Angiography in the Thirteen-Lined Ground Squirrel. Transl Vis Sci Technol 2021 Jul 01;10(8):5

Date

07/08/2021

Pubmed ID

34232271

Pubmed Central ID

PMC8267221

DOI

10.1167/tvst.10.8.5

Scopus ID

2-s2.0-85111034709 (requires institutional sign-in at Scopus site)

Abstract

PURPOSE: To assess the performance of two spectral-domain optical coherence tomography-angiography systems in a natural model of hypoperfusion: the hibernating thirteen-lined ground squirrel (13-LGS).

METHODS: Using a high-speed (130 kHz) OCT-A system (HS-OCT-A) and a commercial OCT (36 kHz; Bioptigen Envisu; BE-OCT-A), we imaged the 13-LGS retina throughout its hibernation cycle. Custom software was used to extract the superior, middle, and deep capillary plexus (SCP, MCP, and DCP, respectively). The retinal vasculature was also imaged with adaptive optics scanning light ophthalmoscopy (AOSLO) during torpor to visualize individual blood cells. Finally, correlative histology with immunolabeled or DiI-stained vasculature was performed.

RESULTS: During euthermia, vessel density was similar between devices for the SCP and MCP (P = 0.88, 0.72, respectively), with a small difference in the DCP (-1.63 ± 1.54%, P = 0.036). Apparent capillary dropout was observed during torpor, but recovered after forced arousal, and this effect was exaggerated in high-speed OCT-A imaging. Based on cell flux measurements with AOSLO, increasing OCT-A scan duration by ∼1000× would avoid the apparent capillary dropout artifact. High correspondence between OCT-A (during euthermia) and histology enabled lateral scale calibration.

CONCLUSIONS: While the HS-OCT-A system provides a more efficient workflow, the shorter interscan interval may render it more susceptible to the apparent capillary dropout artifact. Disambiguation between capillary dropout and transient ischemia can have important implications in the management of retinal disease and warrants additional diagnostics.

TRANSLATIONAL RELEVANCE: The 13-LGS provides a natural model of hypoperfusion that may prove valuable in modeling the utility of OCT-A in human pathologies associated with altered blood flow.

Author List

Salmon AE, Chen RC, Atry F, Gaffney M, Merriman DK, Gil DA, Skala MC, Collery R, Allen KP, Buckland E, Pashaie R, Carroll J

Authors

Kenneth Paul Allen DVM Associate Professor in the Research Office department at Medical College of Wisconsin
Joseph J. Carroll PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin
Ross F. Collery PhD Assistant Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Angiography
Animals
Humans
Ophthalmoscopy
Retina
Sciuridae
Tomography, Optical Coherence