An Automatic, Intercapillary Area-Based Algorithm for Quantifying Diabetes-Related Capillary Dropout Using Optical Coherence Tomography Angiography

Abstract

Structured Abstract PURPOSE To develop a robust, sensitive, and fully automatic algorithm to quantify diabetes related capillary dropout using optical coherence tomography (OCT) angiography (OCTA). METHODS A 1050 nm wavelength, 400 kHz A-scan rate swept-source OCT prototype was used to perform volumetric OCTA imaging over 3 mm × 3 mm fields in normal controls (n = 5), patients with diabetes without diabetic retinopathy (DR) (n = 7), patients with non-proliferative diabetic retinopathy (NPDR) (n = 9), and patients with proliferative diabetic retinopathy (PDR) (n = 5); for each patient, one eye was imaged. A fully automatic algorithm to quantify intercapillary areas was developed. RESULTS Of the 26 evaluated eyes, the segmentation was successful in 22 eyes (85%). The mean values of the 10 and 20 largest intercapillary areas, either including or excluding the foveal avascular zone, showed a consistent trend of increasing size from normal control eyes, to eyes with diabetic retinopathy but without DR, to NPDR eyes, and finally, to PDR eyes. CONCLUSIONS OCTA based screening and monitoring of DR patients is critically dependent on automated vessel analysis. The presented algorithm was able to automatically extract an intercapillary area based metric in patients having various stages of DR. Intercapillary area based approaches are likely more sensitive to early stage capillary dropout than vascular density based methods.

Retinal Nonperfusion Relationship to Arteries or Veins Observed on Widefield Optical Coherence Tomography Angiography in Diabetic Retinopathy

“…Recent studies using OCTA as well as FA have quantitatively evaluated capillary nonperfusion areas in DR, and have generally demonstrated that capillary nonperfusion increases with increasing DR severity. 13,20,21 The results herein agree with these findings (Table). Furthermore, compared to FA, OCTA can also visualize periarterial capillary-free zones [16][17][18] and vessel connections at the level of precapillary arterioles and venules.…”

Relationship of intercapillary area with visual acuity in diabetes mellitus: an optical coherence tomography angiography study

“…FAZ circularity is proposed to quantify deformation of FAZ indicating disruption of the terminal capillary ring at the fovea 16. Nevertheless, such association between FAZ circularity and VA has not been found by Durbin et al 8.…”

OCT angiography and visible-light OCT in diabetic retinopathy

“…Automated algorithms quantifying DMI from full retinal thickness angiograms have shown the ability to distinguish DR from healthy controls (Hwang et al, 2016a), as well as trends of avascular area increasing with disease severity (Schottenhamml et al, 2016). Demonstrating the usefulness of OCTA in segmenting the individual capillary plexuses, studies showed that grading DMI in the three distinct plexuses (SCP, MCP, and DCP) had a higher sensitivity and specificity for determining DR versus healthy controls, as well as determining DR stage, compared to grading full retinal thickness angiograms (Zhang et al, 2016b, Hwang et al, 2016b).…”