Intra-session repeatability of quantitative metrics using widefield optical coherence tomography angiography (OCTA) in elderly subjects

Jimmy Hong; Bingyao Tan; Nguyen Duc Quang; Preeti Gupta; Emily Lin; Damon Wong; Marcus Ang; Ecosse Lamoureux; Leopold Schmetterer; Jacqueline Chua

doi:10.1111/aos.14327

Intra-session repeatability of quantitative metrics using widefield optical coherence tomography angiography (OCTA) in elderly subjects

Acta Ophthalmol. 2020 Aug;98(5):e570-e578. doi: 10.1111/aos.14327. Epub 2019 Dec 12.

Authors

Jimmy Hong^{1

2}, Bingyao Tan¹, Nguyen Duc Quang¹, Preeti Gupta¹, Emily Lin¹, Damon Wong^{1

3}, Marcus Ang^{1

4}, Ecosse Lamoureux^{1

4}, Leopold Schmetterer^{1

2

3

4

5

6}, Jacqueline Chua^{1

4}

Affiliations

¹ Singapore Eye Research Institute, Singapore National Eye Centre, Singapore City, Singapore.
² Department of Ophthalmology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore City, Singapore.
³ School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore City, Singapore.
⁴ Academic Clinical Program, Duke-NUS Medical School, Singapore City, Singapore.
⁵ Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
⁶ Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.

Abstract

Purpose: To assess the repeatability of retinal vascular metrics using different postprocessing methods as obtained from the swept-source optical coherence tomography angiography (SS-OCTA).

Methods: Thirty-two participants (63% males; mean [SD] age, 70 [7] years) underwent SS-OCTA imaging (PLEX^® Elite 9000, Carl Zeiss Meditec, Inc., Dublin, USA). Each participant underwent 2 repeated scans of 2 scan protocols: a macular-centred 3 × 3-mm² and a widefield 12 × 12-mm² for a total of 4 acquisitions. Images of superficial vascular plexuses (SVP) and deep vascular plexuses (DVP) were processed using different filters to generate the perfusion density (PD) and vessel density (VD). Vessel enhancement filters ranged from vessel targeted (Hessian and Gabor filters), classical denoising (Gaussian filter), to a scale-selective adaption (modified Bayesian residual transform [MBRT]). Intra-session repeatability of the different filters and their correlation with the original data set were calculated with the intraclass correlation coefficient (ICC) and Pearson's r.

Results: Of the 32 eyes, 17 and 15 were right and left eyes, respectively. For 3 × 3-mm² scans, both MBRT and Gabor filters yielded very good repeatable PD and VD (both ICCs > 0.87) values. Gabor filter was the most correlated with the original data set for the OCTA metrics (r = 0.95-0.97). For 12 × 12-mm² scans, MBRT filter produced good-to-moderate ICC values for SVP (ICC>0.89) and DVP (ICC>0.73) metrics. Both the MBRT and Gabor filters were highly correlated with the original 12 × 12-mm² scan data set (r = 0.96-0.98). The ICCs for the agreement between 3 × 3-mm² and cropped 12 × 12-mm² were high only for the PD values at the SVP layer and were poor for the VD at SVP and DVP measurements (ICC < 0.50).

Conclusion: Our findings show that with the proper choice of postimaging processing methods, SS-OCTA metrics can be obtained with high repeatability, which supports its use in various clinical settings.

Keywords: filters; macula; optical coherence tomography angiography; perfusion density; repeatability; vessel density.

Abstract

Grants and funding