Abstract
Purpose :
Comparability between optical coherence tomography (OCT) angiograms generated by various devices remains controversial. And previous studies didn't register OCT angiograms to a same retinal region or evaluate quality of angiograms, which might increase bias in quantitative analysis. This study aimed to evaluate the agreement and reliability of optical coherence tomography (OCT) angiograms of 4 different commercial devices by evaluating image quality and analyzing angiograms, including vessel density (VD) and vessel length density (VLD), of superficial capillary plexus (SCP) and deep capillary plexus (DCP).
Methods :
Consecutive healthy volunteers were imaged by four OCT angiography (OCTA) devices, including Optovue RTVue XR Avanti, Zeiss Cirrus HD-OCT 5000, Topcon Swept source DRI OCT Triton, and Heidelberg Spectralis OCTA, using a 3×3 mm volume scan pattern centered on the fovea. After registration, image quality were evaluated using contrast, signal noise ratio (SNR), and accuracy in avascular area. VD and VLD of these devices were used for angiogram analysis. ANOVA was used to compare the metrics above. Bland-Altman analysis, interclass correlation coefficient, and Pearson correlation test were used to analyze agreement, reliability, and correlation of VD and VLD of various OCT angiograms. Linear regression analysis was used to analyze the relationship between image quality and both VD and VLD.
Results :
16 eyes from 8 healthy subjects were enrolled. Only Optovue and Topcon exhibited no significant difference at SCP on contrast, SNR, and accuracy in avascular area (p=0.993, 0.235, 0.106, respectively). Only Optovue and Topcon at DCP had a relatively acceptable comparability on both VD (agreement range=13.78, ICC=0.853, r=0.744) and VLD (agreement range=0.02, ICC=0.642, r=0.483). Regression analysis revealed that contrast and accuracy in avascular area were significantly associated with VD (beta=0.084, -0.930; p=0.031, <0.001, respectively) and VLD (beta=0.518, -0.267, respectively; p<0.001). VD is strongly correlated with accrucay in avascular area (r=-0.954), and VLD is correlated to contrast and SNR (r>0.600) significantly.
Conclusions :
Our results suggest that image registration and evaluation of image quality are needed before analysis and comparison of OCT angiograms. Absolute values calculated with various OCTA devices are not directly interchangeable. Longitudinal monitoring should be carried out with a same OCTA device.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.