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Richard Rosen, Jorge S Andrade Romo, Maria V. Castanos Toral, Davis B Zhou, Patricia Garcia, Alexander Barash, Rishard Weitz, Toco YP Chui; Reference-Based OCT Angiography Perfusion Density Mapping for Identifying Acute and Chronic Changes in Eyes with Retinopathy over Time. Invest. Ophthalmol. Vis. Sci. 2019;60(11):003.
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Assessing non-perfusion and re-perfusion using perfusion density change over time can be challenging given the variability even within a single subject. Using a reference-based perfusion density change mapping approach we evaluated a variety of acute and chronic retinopathies.
28 patients (5 age-related macular degeneration-AMD, 10 diabetic retinopathy-DR, 9 retinal vein occlusion-RVO, 2 sickle cell retinopathy-SCR, and 2 radiation retinopathy-RR) and 20 controls were imaged using SDOCT (Optovue). Two 3x3mm parafoveal OCT-A scans were obtained for controls. Acute perfusion changes were assessed in 19 patients before and immediately after intravitreal injections (Fig. Top row). Chronic perfusion changes were assessed in 9 patients with follow up intervals ranging from 6 months to 4 years (Fig. bottom row). Subjects with signal strength index difference between each pair of OCT-As <10 were included for image processing. Image registration was performed for each pair of OCT-As using ImageJ. OCT-A image processing and perfusion density computation were performed using MATLAB as previously described ( ARVO 2018 E-Abstract 4944). Within subject variability of perfusion densities were computed between scans in all controls. Identification of non-perfusion and re-perfusion over time was performed in patients (Fig. Right column). Non-perfusion and re-perfusion area in patients were defined as difference in perfusion density between scans with lower than 0.1% or higher than 99.9% of the normal distribution based on the within-subject variability in controls, respectively.
In patients with acute perfusion changes, mean±SD of non-perfusion and re-perfusion area were 13.20±11.12% and 3.13±5.03%, respectively. Highest acute non-perfusion and re-perfusion area changes were found in patients with RR and RVO, respectively. In patients with chronic perfusion changes, mean±SD of non-perfusion and re-perfusion area were 4.39±6.92% and 1.77±2.38%, respectively. Highest chronic non-perfusion and re-perfusion area changes were found in patients with RVO and DR, respectively.
OCT-A non-perfusion and re-perfused areas were identified in eyes with acute and chronic changes. We have demonstrated a reference-based mapping of non-perfusion and re-perfusion which allows qualitative and quantitative analysis of perfusion density change in OCT-A scans.
This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.
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