Automated Quantification of Nonperfusion Areas in 3 Vascular Plexuses With Optical Coherence Tomography Angiography in Eyes of Patients With Diabetes

Abstract

<div class="section"> <a class="named-anchor" id="ab-eoi180046-1"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e346">Question</h5> <p id="d808191e348">How useful are automatically quantified nonperfusion parameters from projection-resolved optical coherence tomography angiography in patients with diabetes? </p> </div><div class="section"> <a class="named-anchor" id="ab-eoi180046-2"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e351">Findings</h5> <p id="d808191e353">In this cross-sectional study of 71 patients with diabetes and 39 healthy control individuals, avascular areas detected from projection-resolved optical coherence tomography angiography retinal plexuses distinguished between control individuals and various levels of diabetic retinopathy severity. These biomarkers were less dependent on age and signal strength and more sensitive than some commercially available vessel density measurements. </p> </div><div class="section"> <a class="named-anchor" id="ab-eoi180046-3"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e356">Meaning</h5> <p id="d808191e358">Automatically quantified avascular areas from projection-resolved optical coherence tomography angiography of individual plexuses in patients with diabetes may offer a more reliable, sensitive method to evaluate diabetic vascular abnormalities than previous methods. </p> </div><div class="section"> <a class="named-anchor" id="ab-eoi180046-4"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e362">Importance</h5> <p id="d808191e364">Diabetic retinopathy (DR) is a leading cause of vision loss that is managed primarily through qualitative clinical examination of the retina. Optical coherence tomography angiography (OCTA) may offer an objective and quantitative method of evaluating DR. </p> </div><div class="section"> <a class="named-anchor" id="ab-eoi180046-5"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e367">Objective</h5> <p id="d808191e369">To quantify capillary nonperfusion in 3 vascular plexuses in the macula of eyes patients with diabetes of various retinopathy severity using projection-resolved OCTA (PR-OCTA). </p> </div><div class="section"> <a class="named-anchor" id="ab-eoi180046-6"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e372">Design, Setting, and Participants</h5> <p id="d808191e374">Cross-sectional study at a tertiary academic center comprising 1 eye each from healthy control individuals and patients with diabetes at different severity stages of retinopathy. Data were acquired and analyzed between January 2015 and December 2017. </p> </div><div class="section"> <a class="named-anchor" id="ab-eoi180046-7"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e377">Main Outcomes and Measures</h5> <p id="d808191e379">Foveal avascular zone area, extrafoveal avascular area (EAA), and the sensitivity of detecting levels of retinopathy. </p> </div><div class="section"> <a class="named-anchor" id="ab-eoi180046-8"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e382">Results</h5> <p id="d808191e384">The study included 39 control individuals (20 women [51%]; mean [SD] age, 43.41 [19.37] years); 16 patients with diabetes without retinopathy (8 women [50%]; mean [SD] age, 56.50 [12.43] years); 23 patients with mild to moderate nonproliferative DR (18 women [78%] ; mean [SD] age, 62.48 [10.55] years); and 32 patients with severe nonproliferative DR or proliferative DR (12 women [38%]; mean age, 53.41 [14.05] years). Mean (SD) foveal avascular zone area was 0.203 (0.103) mm ² for control individuals, 0.192 (0.084) mm ² for patients with diabetes without retinopathy, 0.243 [0.079] mm ² for mild to moderate nonproliferative DR, and 0.359 (0.275) mm ² for severe nonproliferative DR or proliferative DR. Mean (SD) EAA in whole inner retinal slab in these groups, respectively, were 0.020 (0.031) mm ², 0.034 (0.047) mm ², 0.038 (0.040) mm ², and 0.237 (0.235) mm ². The mean (SD) sum of EAA from 3 segmented plexuses in each of the respective groups were 0.103 (0.169) mm ², 0.213 (0.242) mm ², 0.451 (0.243) mm ², and 1.325 (1.140) mm ². With specificity fixed at 95%, using EAA in inner retinal slab, the sensitivity of detecting patients with diabetes from healthy control individuals was 28% (95% CI, 18%-40%), 31% for patients with DR (95% CI, 19%-45%), and 47% for patients with severe DR (95% CI, 29%-65%) from whole inner retinal EAA. With the sum of EAA from 3 individual plexuses, the sensitivities were 69% (95% CI, 57%-80%), 82% (95% CI, 70%-91%), and 97% (95% CI, 85%-100%), respectively. Avascular areas were not associated with signal strength index. The commercial vessel density from the 2-plexus scheme distinguished the groups with lower sensitivity and were dependent on SSI. </p> </div><div class="section"> <a class="named-anchor" id="ab-eoi180046-9"> <!-- named anchor --> </a> <h5 class="section-title" id="d808191e425">Conclusions and Relevance</h5> <p id="d808191e427">Automatically quantified avascular areas from a 3-layer segmentation scheme using PR-OCTA distinguished levels of retinopathy with a greater sensitivity than avascular areas from unsegmented inner retinal slab or measurements from a commercially available vessel density in 2-layer scheme. Additional studies are needed to investigate the applicability of nonperfusion parameters in clinical settings. </p> </div><p class="first" id="d808191e430">This cross-sectional study quantifies capillary nonperfusion in 3 vascular plexuses in the macula of eyes of patients with diabetes and various retinopathy severity using projection-resolved optical coherence tomography angiography (OCTA). </p>