Purchase this article with an account.
Zhongdi Chu, Qinqin Zhang, Chieh-Li Chen, Fengyi Luo, Cecilia Lee, James L Kinyoun, Ruikang K Wang; Repeatability and Reproducibility of Quantifying Parafoveal Vessel Density in Normal Subjects with OCT-based Microangiography. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):5958.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To demonstrate the reliability of OCT-based microangiography (OMAG) for non-invasive, label-free in vivo imaging of the retinal microvasculature in macular region of normal subjects and for the measurement of vessel density in central fovea and parafoveal quadrants.
A prospective, observational study was conducted with ten normal subjects (twenty eyes; age = 30.9±7.17). Each subject was scanned three times per eye with a Cirrus HD-5000 OCT-angiography prototype using OMAG scanning protocol. The retinal microcirculation was depicted as an en face image. Two masked graders performed segmentation of the resulting OMAG images, outlined the foveal avascular zone (FAZ) with ellipse or free-hand drawing approach and performed independent vessel density quantification. The parafoveal and foveal regions were outlined with circles of diameters of 2.5mm and 1.5mm; vessel density was calculated for central foveal region (FAZ excluded) and in quadrants for parafovea. Descriptive statistics, repeatability and reproducibility were calculated.
The vessel density of defined sub-field varied among subjects (range of 0.136-0.288). The mean values of each sub-field were 0.223±0.022 for parafoveal superior quadrant, 0.22±0.022 for parafoveal inferior quadrant, 0.234±0.022 for parafoveal nasal quadrant, 0.23±0.024 for parafoveal temporal quadrant and 0.222±0.02 for central fovea. There were no statistically significant differences among four parafoveal quadrants, but statistically significant differences were observed between parafoveal nasal and central foveal regions (p = 3e-5) as well as between parafoveal temporal and central foveal regions (p = 0.0149). The measurements were reliable: the repeatability (%) was 9.7% (Sr = 0.021), the reproducibility (%) was 5.3% (SR = 0.012), and the intra-class coefficient (ICC) was 0.96 while the coefficient of variance was 5.4%.
OMAG is a noninvasive 3D imaging technique that can provide depth-resolved retinal microvasculature information with capillary level resolution in real-time. Blood flow distribution in macular region can be easily identified and allow repeatable and reproducible parafoveal vessel density measurements.
This PDF is available to Subscribers Only