Abstract
Purpose :
To study the temporal and spatial variability in OCT-Angiography measurement across the branching order of the vascular network and across instruments.
Methods :
We measured 5 normal subjects a total of 10 times within a 30 minute session and recorded the OCT-Angiography scan according to the manufacturer's guidelines. We imaged the subjects in three difference instruments, the Heidelberg Engineering Spectralis OCT, the Optovue AngioVue and the Zeiss Cirrus 5000 Angioplex.
We used the build-in eye tracking feature for each instrument to align the follow-up exam of each scan with the first scan.
To analyze the data, we exported the OCT-Angiogram to ImageJ. In ImageJ we aligned the images to compensate for small variation in image alignment between repeat scans. We calculated the coefficient of variation (COV) for each blood vessel along the vessel tree.
Results :
We found that the variability in OCT Angiography measurements is higher in smaller blood vessels and capillaries than in larger blood vessels. The variability was different between the three instruments.
Conclusions :
This study compared the temporal and spatial variability in OCT Angiography measurements in normal subjects. The high temporal variability in smaller blood vessels indicates that the significance of OCT Angiography measurements based on a single measurement may be impacted. The reason for the high variability might be the snapshot approach of all OCT Angiography devices that capture only a fraction of the cardiac cycle in each vessel segment. Therefore, the natural variation in bloodflow may not be accurately sampled by a single OCT Angiogram.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.