ABSTRACT
Purpose: To characterize the relationship between diabetic macular ischemia (DMI) delineated by optical coherence tomography angiography (OCTA) and microaneurysms (MAs) identified by fundus fluorescein angiography (FFA). Methods: Patients with diabetic retinopathy (DR) who underwent OCTA and FFA were retrospectively identified. FFA images were cropped and aligned with their respective OCTA images using i2k Align Retina software (Dual?Align, Clifton Park, NY, USA). Foveal avascular zone (FAZ) and ischemic areas were manually delineated on OCTA images, and MAs were marked on the corresponding FFA images before overlaying paired scans for analysis (ImageJ; National Institutes of Health, Bethesda, MD, USA). Results: Twenty?eight eyes of 20 patients were included. The average number of MAs identified in cropped FFA images was 127 ± 42. More DMI was noted in the superficial capillary plexus (SCP; 36 ± 13%) compared to the deep capillary plexus (DCP; 28 ± 14%, P < 0.001). Similarly, more MAs were associated with ischemic areas in SCP compared to DCP (92.0 ± 35.0 vs. 76.8 ± 36.5, P < 0.001). Most MAs bordered ischemic areas; fewer than 10% localized inside these regions. As DMI area increased, so did associated MAs (SCP: r = 0.695, P < 0.001; DCP: r = 0.726, P < 0.001). Density of MAs surrounding FAZ (7.7 ± 6.0 MAs/mm2) was similar to other DMI areas (SCP: 7.0 ± 4.0 MAs/mm2, P = 0.478; DCP: 9.2 ± 10.9 MAs/mm2, P = 0.394). Conclusion: MAs identified in FFA strongly associate with, and border areas of, DMI delineated by OCTA. Although more MAs are localized to SCP ischemia, the concentration of MAs associated with DCP ischemia is greater. By contrast, few MAs are present inside low?flow regions, likely because capillary loss is associated with their regression.
ABSTRACT
Purpose: The present study aims to determine the macular and choroidal optical coherence tomography angiography (OCTA) biomarkers in the assessment and monitoring of diabetic macular edema (DME) and diabetic macular ischemia (DMI) in patients with non?proliferative diabetic retinopathy (NPDR). Methods: In this cohort study, a total of 176 eyes of 110 patients with NPDR were investigated at our institute over a period of 10 months. Eyes were divided into four groups based on the severity of NPDR. Each eye was subjected to OCTA (Topcon 3D OCT?1 Maestro2) macula 6 × 6 mm2 en face. It features IMAGEnet 6 software for dynamic viewing of OCTA and imaging data. Four OCTA biomarkers for the macula were identified: foveal avascular zone area (FAZ area), foveal avascular zone contour irregularity (FAZ?CI), capillary dropout areas (CDA), and perifoveal intercapillary areas (PICA). The choroidal OCTA biomarker was the number of choroidal circulation flow voids (CCFV). For all analyses, P < 0.05 was considered statistically significant. Results: Increase in FAZ area and number of CDA were statistically significant (p < 0.0001) with an increase in central foveal thickness, suggesting a correlation of ischemic changes with an increase in DME. FAZ?CI, enlarged PICA, and CCFV were significantly associated with more severe NPDR patients. Conclusion: A correlation between DME and DMI in a patient of NPDR and its progression can be evaluated in a single visit. A unique feature of our study is it revealed novel diagnostic biomarkers of OCTA for DMI and DME.
ABSTRACT
Diabetic macular ischemia (DMI) is one of the manifestation of diabetic retinopathy (DR).It could be associated with diabetic macular edema (DME),which may affect the vision of DR patients.FFA is the gold standard for the diagnosis of DMI,but with the advent of OCT angiography,a more convenient and diversified method for the evaluation of DMI has been developed,which makes more and more researchers start to study DMI.Intravitreal injection of anti-VEGF has become the preferred treatment for DME.When treating with DME patients,ophthalmologists usually avoid DMI patients.But if intravitreal anti-VEGF should be the contradiction of DME is still unclear.To provide references to the research,this article summarized the risk factors,assessment methods and influence of DMI.This article also analyzed the existing studies,aiming to offer evidences to a more reasonable and effective treatment decision for DME individual.