Fractal dimension analysis of OCTA images of diabetic retinopathy using circular mass-radius method

Abstract

BACKGROUND AND OBJECTIVE: To quantify fractal dimension (FD) by mass-radius method in optical coherence tomography angiography (OCTA) images and characterize microvascular differences in eyes with and without diabetic retinopathy (DR). PATIENTS AND METHODS: A retrospective study was conducted using OCTA images of 3 mm × 3 mm and 6 mm × 6 mm scans for superficial and deep capillary plexuses from 49 control eyes and 58 eyes with DR. RESULTS: Analysis of variance showed a significant difference between the FD of control and diabetic eyes in deep plexus scans, and the 3 mm × 3 mm superficial plexus scan (P < .05). In the 3 mm × 3 mm superficial plexus, the FD of severe nonproliferative DR (NPDR) and proliferative DR (PDR) were significantly lower compared to control. The scans of the deep plexus showed only severe NPDR was significantly reduced in the 6 mm × 6 mm scan, whereas moderate NPDR, severe NPDR, and PDR were significantly lower in the 3 mm × 3 mm scan. CONCLUSION: The study suggests the use of FD as a measure of microvascular dropout in DR.