Capillary Perfusion Deviation Mapping in Diabetic Retinopathy using Optical Coherence Tomography Angiography (OCTA) - A Novel Single-Scan Approach

Abstract

Purpose : To evaluate an automatic single-scan OCTA capillary density deviation mapping approach that is retinal eccentricity-specific and based on an age-matched database in patients with diabetic retinopathy.

Methods : Healthy controls and diabetic patients were imaged using a commercial SDOCT (Avanti RTVue-XR; Optovue). A 3x3 mm macular OCTA scan was obtained for each participant. Axial lengths were obtained for retinal magnification correction . Full vascular layer OCTA (all vessels located between the inner limiting membrane and 70-µm below the posterior boundary of the inner plexiform layer) was analyzed. (Fig. A). A capillary density map was created after the removal of large vessels on the full layer OCTA (Fig. B). Capillary density map for a given individual full layer OCTA was then compared against a retinal eccentricity-specific and age-matched database based upon 241 controls (age range: 5-81years). A deviation map highlighting regions with capillary density below 5% (in yellow) and 1% (in red) of the reference database were generated (Fig. C). Areas of capillary density below 5% and 1% on the deviation map for each group were compared using one-way ANOVA and post-hoc Tukey-Kramer test.

Results : 30 controls and 78 diabetic eyes (30 - NoDR(no clinical observable retinopathy); 22 NPDR; and 26 PDR) were imaged. The mean±SD of yellow areas were for the the control, NoDR, NPDR, and PDR groups were 4.5±9.6%, 2.7±4.3%, 17.2±17.2%, and 29.5±18.9%, respectively. Similarly, the mean±SD of the red areas for the control, NoDR, NPDR, and PDR groups were 0.8±2.7%, 0.4±1.2%, 6.8±9.8%, and 13.0±13.1% in, respectively. While there were no significant differences between the control and NoDR groups, percentage of yellow and red areas differed significantly between all other groups (p<0.05).

Conclusions : We present a novel single-scan capillary perfusion deviation mapping method which can detect local perfusion deficits and quantify the extent of perfusion abnormality in different stages of diabetic retinopathy (DR) . It may prove clinically useful for grading disease severity and earlier diagnosis of diabetic retinopathy.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

OCTA deviation mapping of capillary density in a patient with PDR. A) Full vascular layer OCTA. B) Capillary density map after removal of large blood vessels. C) Deviation map based on a retinal eccentricity-specific and age-matched database.