Intrasession repeatability of OCTA 4.5mm and 6mm image scans for glaucomatous and non-glaucomatous eyes

Abstract

Purpose : The optimal protocols for using optical coherence tomography angiography (OCTA) for glaucoma patient care is under investigation. We conducted a prospective observational imaging study of glaucoma patients and suspects to determine the OCTA’s intrasession repeatability for 4.5x4.5mm and 6x6 image scans.
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Methods : For 46 consecutive patients, two peripapillary 4.5mm and 6mm OCTA scans were obtained on the same day. Images with a signal strength >6, and minimal decentration were analyzed. Inclusion was further determined by 2 graders using a custom quality scale (1-7) for each characteristic: motion artifact, floaters, fadedness, missing data. Vessel Area Density (VAD) and Flux of the annulus around the optic nerve head were obtained using Zeiss quantification software (Cirrus 11.0, Zeiss). Images were evaluated for intrasession repeatability of OCTA metrics using intraclass correlation coefficient (ICC).

Results : From the initial 46 patients, 30 were eligible for inclusion. Their mean age was 47.4±14.6 years with 12 males and 18 females. A total of 180 images from 45 eyes were analyzed.

The mean signal strength of 4.5mm images was 9.7 ± 0.6 and the mean total quality score was 26.4 ± 1.6 (n=180) based on the 2 graders’ scores. (Table 1) The ICC for VAD of the annulus was 0.94 (95% CI 0.90-0.97) and 0.95 (95% CI 0.91-0.97) for Flux for the 4.5 mm scans (Table 2). When comparing the ICC for glaucoma patients to glaucoma suspects, for VAD it was 0.94 (95% CI 0.83-0.98) vs 0.89 (95% CI 0.79-0.95), respectively. The ICC for Flux for glaucoma patients and suspects were 0.95 (95% CI 0.85-0.98) vs 0.88 (95% CI 0.77-0.94), respectively.

The mean signal strength of 6mm images was 9.4 ± 0.8 and the mean total quality score was 26.2 ± 1.8 (n=180) based on the 2 graders’ scores. The ICC for VAD was 0.94 (95% CI 0.90-0.97) and the ICC for Flux was 0.96 (95% CI 0.93-0.98). For 6mm scans, when comparing glaucoma patients to suspects, the ICC for VAD was 0.96 (95% CI 0.87-0.99) vs 0.89 (95% CI 0.79-0.95), and the ICC for Flux was 0.98 (95% CI 0.93-0.99) vs 0.90 (95% CI 0.80-0.95), respectively.

Conclusions : OCTA 4.5mm and 6mm scans for the same patient taken on the same date demonstrated high repeatability based on ICC for VAD and for Flux. 4.5mm and 6mm images have high repeatability for both glaucoma patients and suspects.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

OCTA Quality Parameters (Scale 1-7)

 

ICC of Quadrant OCTA Parameters