Estimating Retinal Blood Flow Velocities by Optical Coherence Tomography

Abstract

IMPORTANCE While optical coherence tomography (OCT) angiography has been considered to evaluate retinal capillary blood flow instead of fluorescein angiography, the reflectance pattern of blood vessels on structural OCT might also provide retinal capillary flow data in the absence of fluorescein angiography. This potential has been insufficiently explored, despite promising data concerning a possible relationship between the reflectance pattern of blood vessels and their perfusion velocity in a laboratory setting.OBJECTIVE To evaluate the potential of retinal blood flow velocity estimation by structural OCT. DESIGN, SETTING, AND PARTICIPANTSCross-sectional observational study conducted from June to November 2015 at a tertiary clinical referral center. Sixty arteries (the superior and inferior temporal arteries) from 30 eyes of 30 patients (17 female, 13 male) were included in the study. MAIN OUTCOMES AND MEASURESBased on the intraluminal contrast patterns of retinal arteries on OCT, 3 independent graders categorized the blood flow velocities as low, medium, or high. These results and the results from a software-based intraluminal contrast analysis were compared with the retinal blood flow velocities measured by video fluorescein angiography.RESULTS Among the 30 eyes of 30 patients (mean [SD] age, 72.6 [12.3] years; 17 female, 13 male), 15 were controls without retinal occlusion, 6 had a branch retinal artery occlusion, and 9 had a central retinal artery occlusion. When discriminating between low flow velocities and medium or high flow velocities, the graders' sensitivity ranged from 88.2% to 100%

Rodent retinal circulation organization and oxygen metabolism revealed by visible-light optical coherence tomography

“…The recent advent of visible light OCT (vis-OCT) [9] allows retinal oximetry [10,11] with enhanced extinction coefficient contrast between oxy-and deoxy-hemoglobin [12], as well as the retinal angiography and retinal flowmeter by Doppler OCT [13,14], which had been accomplished previously in near infrared OCT. Although the technique has been successfully applied to human retina [15,16] and other tissue [17] imaging, its great potential on retinal imaging by combing all these functional features have not been fully investigated.…”

Vitreous hyper-reflective dots in pseudophakic cystoid macular edema assessed with optical coherence tomography

“…The device used a bandwidth of 297 nm and a wavelength of 815 nm. [ 14 , 22 ]. A built-in eye tracking software (TruTrack) ensured exact position of the recorded scans [ 14 ].…”

“…A built-in eye tracking software (TruTrack) ensured exact position of the recorded scans [ 14 ]. Sections were received using the high-speed mode with a resolution of 7 μm axially x 14μm laterally and a distance of 240μm between sections [ 22 ]. CME was defined as macular thickness >300 μm and the presence of intraretinal hypo-reflective cysts within the ETDRS (Early Treatment Diabetic Retinopathy Study) circle [ 2 , 8 , 23 ].…”

“…The OCT image included central subfield thickness (CST) in μm and cube volume (CV) in mm 3 . The CV is a 6-mm volume grid according to the ETDRS, which is automatically calculated with the built-in software by means of the formula surface x thickness [ 14 , 22 ]. In addition, VHDs, defined as clearly visible hyper-reflective dots of variable size of >20 μm in diameter, were assessed ( Fig 1 ) [ 8 ].…”

Ocular Manifestations of Alzheimer’s and Other Neurodegenerative Diseases: The Prospect of the Eye as a Tool for the Early Diagnosis of Alzheimer’s Disease

“…For this purpose, in September 2016, they began a clinical trial ( ClinicalTrials.gov Identifier: NCT02663531 ) evaluating the relationship between neural activity and blood flow, in induced flicker light hyperaemia in the retina, as a possible biomarker for AD. Furthermore, they assessed structural parameters such as retinal nerve fibre layer thickness and function parameters such as ocular blood flow and retinal oxygenation [ 132 , 133 ]. According to the results, neuritic plaques were detected in representative cortical regions, suggesting OCTA as a useful tool for three-dimensional imaging of retinal A β accumulation [ 134 , 135 ].…”