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TAI-CHI LIN, Priyanka Gogte, Neal Palejwala, Anoush Shahidzadeh, Sujit Itty, Mark S Humayun, Andrew A Moshfeghi, Hossein Ameri, Zhongdi Chu, Ruikang K Wang, Jeremy D Wolfe, Pravin U Dugel, Amir H Kashani; Quantitative spectral-domain optical coherence tomography angiography (OCTA) of Diabetic Retinopathy (DR) Severity. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1653. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To quantify and compare capillary density and morphology in macular 3x3 and 6x6mm OCTA scans of subjects with DR.
Multicenter, retrospective, cross-sectional study of adult subjects with and without DR. Retinal microvasculature was assessed with a commercially available OCTA (Cirrus AngioPlex) and correlated with clinical exam. A custom MATLAB program was used to calculate indices of capillary density and morphology from segmented and non-segmented OCTA images using both 3x3 and 6x6mm scan patterns. Microvascular density was quantified as vessel skeleton density (VSD) and vessel area density (VAD), and vessel complexity (VCI) while morphology was quantified as vessel diameter (VD), vessel diameter index (VDI), and vessel perimeter index (VPI). All statistical analysis was done using SAS (SAS Institute Inc.). Pairwise comparisons were computed for the non-segmented (NSR), superficial (SRL), and deep retinal layers (DRL) in both 3x3 and 6x6 mm scans comparing successively worse stages of DR severity. Correlation coefficients with p-values were used to determine the direction and magnitude of correlation between OCTA measures and DR severity.
Sixty-four eyes with DR and 18 healthy eyes from 50 subjects were studied. NSR images showed that VSD and VCI were significantly lower for mild NPDR than normal (p<0.05) as well as for all comparisons between successively more severe DR (p<0.05). Comparisons among SRL images showed that VDI, VD, VAD, VSD, and VCI were significantly different in mild or moderate NPDR compared to normals (p<0.05) and VDI and VD were significantly different in advanced DR (p<0.05). Density and morphology parameters in the DRL were not consistenly and significantly different. Spearman's correlation showed that VDI, VD, VAD, VSD, VPI and VCI were all significantly correlated with DR severity (p<0.001). VDI and VD were positively correlated and VAD, VSD, VPI and VCI were negatively correlated. Significant change in vessel morphology parameters was generally found in 3x3mm of SRL.
Vascular changes in DR can be objectively characterized with OCTA parameters. In general, decreasing capillary density (VAD, VSD, VPI and VCI), and increasing vascular caliber (VD and VDI) were associated with worsening DR. Changes in morphology could mainly be detected using the 3x3mm scans.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
quatitative 3x3mm SRL scans
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