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Zhongdi Chu, Kathryn L Pepple, Ruikang K Wang; Quantitative analysis of choriocapillaris in uveitic and normal subjects with SS-OCT Angiography. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1871.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the difference of choriocapillaris (CC) flow in uveitic and normal subjects with 3mm x 3mm SS-OCT angiography.
Retrospective, cross-sectional study of uveitic and normal subjects. A SS-OCT research prototype Plex-Elite (Carl Zeiss Meditec, Dublin, CA) and OMAG algorithm was used to acquire OCT angiograms of CC. Global average flux index (averaged and normalized OCTA signal intensity of entire CC en face image), global fluctuation flux index (standard deviation of normalized OCTA signal intensity of entire CC en face image) and CC flow void density (percentage of nonflow area in CC against the whole 3mm x 3mm imaging area) were quantified for each cohort. Divergence index (averaged divergence of whole image) was calculated for each uveitic cases against averaged normal OCT angiograms. Two sample t-test were usedfor statistical analysis.
Global average flux index for normal subjects are (0.455, 0.021), with 95% CI of (0.441, 0.469) (n=11); (0.409, 0.039) with 95% CI of (0.386, 0.432) for uveitic cohort (n=14). Global fluctuation flux index for normal subjects are (0.075, 0.007), with 95% CI of (0.070, 0.080); (0.099, 0.027) and 95% CI of (0.084, 0.115) for uveitic cohort. Significant difference were found in both the global average flux index (p=0.0028) and global fluctuation flux index (p= 0.0110). The CC flow void density for normal cohort is (0.066, 0.003), with a 95% CI of (0.064, 0.069) while it is (0.149, 0.020) with 95% CI of (0.138, 0.160). Significant difference were found in CC flow void density too with p=2.9373e-12. The averaged divergence of uveitic subjects is 6.174 and it is found negatively correlated with global average flux index (R2= 0.303, p = 0.0414); positively correlated with global fluctuation flux index (R2= 0.713, p = 0.000147) and positively correlated with choriocapillaris flow voids density (R2= 0.360, p = 0.0234).
Quantitative OMAG analysis can be used to describe the abnormality of CC flow with SS-OCT. Compared to normal subjects, patients with uveitis have lower global average flux index and higher global fluctuation flux index, as well as increased CC flow void density. Divergence index against normal cohorts of OCTA signal were found significantly positively correlated with CC flow void density as well as global fluctuation flux index and negatively correlated with global average flux index in uveitis cohort.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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