Abstract
Purpose :
Optical coherence tomography angiography (OCTA) provides a noninvasive method of visualizing ocular vasculature. Imperfect image registration and changes in vessel diameter with the cardiac cycle may increase variability of vessel caliber measurements, even within the same en-face image. We performed a cross-sectional study to determine the variability of vessel width measurements within a vessel and assessed factors affecting the variability of retinal vessel caliber measurements.
Methods :
A cross-sectional study was performed to examine variation of vascular caliber measurements across sequential OCTA en face images. 48 eyes of 28 patients were imaged in both the disc and macula using the Heidelberg Spectralis OCT2 (Heidelberg, Germany). Two independent masked graders measured multiple measurements of vessel caliber for the five highest resolution veins and arteries involving all peripapillary quadrants centered around the optic disc and involving all perimacular quadrants centered around the fovea. Care was taken to ensure that vessels were measured in segments that did not branch. The standard deviation of all width measurements in a given vessel segment was calculated. The vessel-specific standard deviations were then used as the primary outcome variable and mean standard deviation was compared by age, sex, race, glaucoma status, diabetes, hypertension, pseudophakia, veseel length, image quality, and vessel width.
Results :
A total of 8400 measurements of 420 vessels of 84 OCTA images were included in the analysis. Age, sex, race, glaucoma, diabetes, hypertension, diabetic retinopathy, pseudophakia, and vessel length did not have a significant effect on the within-vessel variability of width (Table 1). Image quality (P<0.01) and mean width of the vessel (P< 0.01) showed significant effect on the within-vessel variability.
Conclusions :
Smaller vessel width and poorer image quality resulted in greater within vessel variability using OCT Angiography.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.