OCT angiography: Measurement of retinal macular microvasculature with Spectralis II OCT angiography – reliability and reproducibility

Abstract

Purpose : Analysis of chorioretinal microvasculature is important in clinical all day life and research. Different Optical Coherence Tomography Angiography (OCT-A) tools with their own analysis software generate diverse data of OCT-A scans, emphasizing the importance of reliability analysis of each OCT-A device and analysis software. The aim of the present study was to investigate the reliability of macular microvasculature characteristics measured with OCT-A of Heidelberg OCT II with a custom-made quantification software (Erlangen-Angio-Tool (EA-Tool) version 1.0).

Methods : Twenty-three eyes of 23 normal subjects were measured by OCT-A (Heidelberg OCT II Spectralis, Heidelberg, Germany). Repeated scans of the macula (size: 2.9 mm x 2.9 mm) including 3 retinochoroidal layers (superficial vascular plexus (SVP), deep capillary plexus (DCP), intermediate vascular plexus (IVP)) were performed with a B-scan thickness of 5.7 µm, separated into 12 sectors (s1-s12). Vessel density (VD) and foveal avascular zone (FAZ) area were calculated for each en face vascular layer, respectively. Reliability was shown by intraclass correlation coefficients (ICC).

Results : (1) Mean VD was in 32.28 ± 3 (SVP), 22.79 ± 3 (ICP) and 25.40 ± 3 (DCP) of the 1^st and 32.62 ± 2 (SVP), 22.89 ± 3 (ICP) and 25.51 ± 3 (DCP) of the 2^nd scan. (2) Sector analysis yielded no significantly different VD of s1-s12 between 1^st and 2^nd scan of SVP, ICP, and DCP, respectively (p>0.05). (3) ICC of VD were excellent (s1, s2, s4, s9, s12 (SVP); s2, s4 (ICP); s3, s4 (DCP)) and good (s5-s8, s10 (SVP); s1, s3, s5, s8, s9, s11, s12 (ICP); s1, s2, s5, s9, s11, s12 (DCP)). (4) Reliability of FAZ showed excellent ICC on 1^st and 2^nd OCT-A scan in SVP, IVP, and DCP. (5) No significant differences of FAZ area in SVP, ICP and DCP were observed between 1^st and 2^nd scan (p>0.05).

Conclusions : As OCT-A data of retinochoroidal microvasculature, quantified with the Erlangen-Angio-Tool, showed a good reliability, EA-Tool can be used as quantification software for analysis of macular vessel density and FAZ metrics in clinical use and research.

This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.

 

Region of interest (i.e. macula) marked with an annulus, subdivided into 12 sectors of 30° (s1-s12).