Investigating the Fractal Dimension of the Foveal Microvasculature in Relation to the Morphology of the Foveal Avascular Zone and to the Macular Circulation in Patients With Type 2 Diabetes Mellitus

Frontiers in Physiology

Nebojsa T. Milosevic¹  Gabor M. Somfai²  Ajay E. Kuriyan³  Joyce C. Shiffman³  Sandra Pineda³  Maja Kostic³  William E. Smiddy³  Ninel Z. Gregori³  Wen-Hsiang Lee³  Jing Tian³  William J. Feuer³  Delia Cabrera DeBuc³  Nathan M. Bates³ 

[1] Department of Biophysics, University of Belgrade, Belgrade, Serbia;Department of Ophthalmology, Semmelweis University, Budapest, Hungary;Miller School of Medicine, Bascom Palmer Eye Institute, University of Miami, Miami, FL, United States;Retinology Unit, Pallas Kliniken, Olten, Switzerland;

关键词: diabetic retinopathy;    fractal analysis;    foveal avascular zone;    blood flow rate;    fractal dimension;   

DOI  :  10.3389/fphys.2018.01233

来源: DOAJ

【 摘 要 】

In this study, we examined the relationship between the fractal dimension (FD), the morphology of the foveal avascular zone (FAZ) and the macular circulation in healthy controls and patients with type 2 diabetes mellitus (T2DM) with and with no diabetic retinopathy (DR). Cross-sectional data of 47 subjects were analyzed from a 5-year longitudinal study using a multimodal optical imaging approach. Healthy eyes from nondiabetic volunteers (n = 12) were selected as controls. Eyes from patients with T2DM were selected and divided into two groups: diabetic subjects with mild DR (MDR group, n = 15) and subjects with DM but without DR (DM group, n = 20). Our results demonstrated a higher FD in the healthy group (mean, 1.42 ± 0.03) than in the DM and MDR groups (1.39 ± 0.02 and 1.35 ± 0.03, respectively). Also, a bigger perimeter, area, and roundness of the FAZ were found in MDR eyes. A significant difference in area and perimeter (p ≤ 0.005) was observed for the MDR group supporting the enlargement of the FAZ due to diabetic complications in the eye. A moderate positive correlation (p = 0.014, R2 = 43.8%) between the FD and blood flow rate (BFR) was only found in the healthy control group. The BFR calculations revealed the lowest values in the MDR group (0.98 ± 0.27 μl/s vs. 1.36 ± 0.86 μl/s and 1.36 ± 0.57 μl/sec in the MDR, DM, and healthy groups, respectively, p = 0.2). Our study suggests that the FD of the foveal vessel arborization could provide useful information to identify early morphological changes in the retina of patients with T2DM. Our results also indicate that the enlargement and asymmetry of the FAZ might be related to a lower BFR because of the DR onset and progression. Interestingly, due to the lack of FAZ symmetry observed in the DM and MDR eyes, it appears that the distribution of flow within the retinal vessels loses complexity as the vascular structures distributing the flow are not well described by fractal branching. Further research could determine how our approach may be used to aid the diagnosis of retinal neurodegeneration and vascular impairment at the early stage of DR.

【 授权许可】

Unknown