Fractal Analysis of Optical Coherence Tomography Angiography in Diabetic Retinopathy With and Without Macular Edema

Abstract

Purpose : To study fractal dimensional of retinal vascular disease in patients with diabetic retinopathy(DR) with and without macular edema using spectral-domain optical coherence tomography angiography(OCTA)

Methods : A retrospective study of 49 control eyes from and 58 diabetic eyes. Of the 58 diabetic eyes, 23 had macular edema and 35 did not. OCTA images were acquired using the RTVue XR Avanti(Optovue,Inc.Fremont, CA).Automated segmentation through the superficial and deep capillary plexuses was obtained. Grayscale OCTA images were standardized and binarized using ImageJ(NIH, Bethesda, Maryland, USA). Fractal box-counting analyses were performed with Fractalyse(TheMA, Besancon Cedex, France). Fractal dimensions(FD) were compared using two-tailed t-tests

Results : The mean foveal and parafoveal thickness of all eyes studied was recorded as per OCTA imaging reports (Table 1).
The mean FD for the superficial and deep plexuses of control eyes was 1.651(SD=0.05391) and 1.677(SD=0.05325), respectively. The mean FD for diabetic eyes without edema was 1.6(SD=0.07) for the superficial plexus and 1.59(SD=0.07) for the deep plexus. There was significant reduction in nonedematous eyes in the superficial plexus (p=0.001) and deep plexus (p=1.49x10^-6).
The mean FD for diabetic eyes with edema was 1.57(SD=0.066) for the superficial plexus and 1.53(SD=0.075) for the deep plexus. There was significant reduction in edematous eyes in the superficial plexus (p=2.08x10^-5) and deep plexus (p=1.85x10^-9)

Conclusions : The OCTA FD is significantly lower in the superficial and deep capillary plexuses in eyes with DR whether macular edema is present or not. Utilization of FD gives an objective criterion to assess microvascular disease burden in DR with and without macular edema

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Pre and post-processing spectral domain optical coherence tomography angiography (SD-OCTA) images. All images are segmented through the superficial capillary plexus.
A. OCTA- control eye.
B. Post-processing, standarization, and binarization of the image shown in (A).
C. OCTA- diabetic retinopathy without macular edema.
D. Post-processing, standarization, and binarization of the image shown in (C).
E. OCTA- diabetic retinopathy with macular edema.
F. Post-processing, standarization, and binarization of the image shown in (E).

 

Table 1. Mean foveal and parafoveal thickness in micromillimeters for control eyes, and diabetic eyes with and without edema.