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Multifractal and Lacunarity Analyses of Microvascular Morphology in Eyes with Diabetic Retinopathy: A Projection Artifact Resolved Optical Coherence Tomography Angiography Study
摘要： Objective: To evaluate the degree of microvascular impairment in diabetic retinopathy using multifractal and lacunarity analyses and to compare the diagnostic ability between traditional Euclidean measures (fovea avascular zone area and vessel density) and fractal geometric features. Methods: This retrospective cross-sectional study included a total of 143 eyes of 94 patients with different stages of diabetic retinopathy. The retinal microvasculature was imaged by projection removed optical coherence tomography angiography. We examined the degree of association between fractal metrics of the retinal microvasculature and diabetic retinopathy severity. The area under the receiver operating characteristic curve was used to estimate the diagnostic performance. Results: With increasing diabetic retinopathy severity, the multifractal spectrum shifted towards the left bottom and exhibited less left skewness and asymmetry. The vessel density, multifractal features and lacunarity measured from the deep capillary plexus were strongly associated with diabetic retinopathy severity. The multifractal feature D5 showed the highest diagnostic ability. The combination of multifractal features further improved the discriminating power. Conclusions: Multifractal and lacunarity analyses can be potentially valuable tools for assessment of microvascular impairments in diabetic retinopathy. Multifractal geometric parameters exhibit a better discriminatory performance than Euclidean measures, particularly for detection of the early stages of diabetic retinopathy.
关键词： diabetic retinopathy,optical coherence tomography angiography,microvascular network,lacunarity,multifractal
更新于2025-09-04 15:30:14
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Evaluation of Ocular Perfusion in Alzheimer’s Disease Using Optical Coherence Tomography Angiography
摘要： Background: There is increasing evidence for the involvement of cerebrovascular factors in Alzheimer’s disease (AD). Objective: To evaluate retinal and optic nerve head perfusion in patients with AD using optical coherence tomography angiography (OCTA), and to analyze the correlations of quantitative OCTA metrics with AD pathology and vascular cerebral lesions in AD patients. Methods: 36 eyes of 36 patients with AD (study group) and 38 eyes of 38 healthy subjects (control group) were prospectively included in this study. OCTA was performed using RTVue XR Avanti with AngioVue. In addition, patients underwent a detailed ophthalmological and neurological examination including Mini-Mental State Examination, cerebral magnetic resonance imaging, and amyloid-β (Aβ) and tau levels in the cerebrospinal fluid (CSF). Results: The flow density in the superficial retinal OCT angiogram of the macula in the study group was significantly lower compared to the control group (p = 0.001). There was a significant correlation between the flow density in the superficial retinal OCT angiogram of the macula, as measured using OCTA, and the Fazekas scale (Spearman’s correlation coefficient = –0.520; p = 0.003). There was no significant correlation between the Aβ or tau levels in the CSF and the flow density data. Conclusion: Patients with AD showed a reduced flow density in the radial peripapillary capillaries layer and in the superficial retinal OCT angiogram when compared with healthy controls. The reduced retinal flow density measured using OCTA is not specifically associated with AD pathology but is associated with the vascular cerebral lesions in AD.
关键词： optical coherence tomography angiography,retinal and optic nerve head perfusion,Alzheimer’s disease,flow density
更新于2025-09-04 15:30:14
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The repeatability of superficial retinal vessel density measurements in eyes with long axial length using optical coherence tomography angiography
摘要： Background: To investigate the repeatability of superficial retinal vessel density measurements in healthy eyes with long axial length (AL) using optical coherence tomography angiography (OCTA). Methods: There were 60 eyes of 31 volunteers enrolled in this cross-sectional observational study. All subjects underwent OCTA, AL and refraction test. The enrolled eyes were divided into the long AL group (26 mm ≤ AL < 28 mm) and normal AL group (22 mm ≤ AL < 26 mm). The vessel length density (VLD), perfusion density (PD), and fovea avascular zone (FAZ) of the superficial retinal vessel were evaluated. Repeatability was assessed by intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Pearson’s r correlation was used to analyze the relation of AL and the absolute difference between two measurements. Results: The 3 × 3 mm scan pattern showed good repeatability with all ICCs over 0.7. For all parameters of all scan patterns, the ICCs of the normal AL group were distinctly higher than those of the long AL group; this finding was also confirmed by Bland-Altman analysis. The correlation analysis of AL and repeatability of OCTA parameters showed significant negative correlations between the ALs and repeatability of VLD in 6 × 6 mm inner ring (r2 = 0.13, p = 0.01), VLD in 6 × 6 mm outer ring (r2 = 0.09, p = 0.02) and PD in 6 × 6 mm outer ring (r2 = 0.08, p = 0.03). Conclusions: The AL and the scanned area will both affect the repeatability of superficial retinal vessel density measurements in OCTA.
关键词： Fovea avascular zone,Vessel length density,Myopia,Optical coherence tomography angiography,Repeatability,Perfusion density
更新于2025-09-04 15:30:14