Quantitative Measurement of Vascular Density and Flow Using Optical Coherence Tomography Angiography in Patients with Vasculitis; Can OCTA detect the vasculitis?
Methods: Patients with uveitis and vasculitis in at least one eye were included and compared with 50 eyes from healthy individuals. The OCTA was done for each patient and control subject. The images were analysed at three capillary plexuses layers (superficial and deep retinal capillary layers and choriocapillaris layer). contact lens was placed on the corneal surface. Corneal edema decreased gradually in one month post-operatively. Results: Fifty-five eyes from 28 patients were enrolled in the study. Studied eyes were categorized into 4 groups: 1-eyes with posterior vasculitis (38 eyes), 2-eyes with peripheral vasculitis without posterior vasculitis (7 eyes), 3-fellow uninvolved eyes of patients with unilateral vasculitis (10 eyes), and 4-eyes of healthy controls (50 eyes). The whole vascular density and parafoveal vascular density in both superficial and deep retinal capillary plexuses were reduced significantly from group 4 to group1. A decreasing trend in macular blood flow was also observed from group 4 followed by group 3, group 2 and group 1 in all three capillary layers including superficial retinal capillary plexus, deep retinal capillary plexus and choriocapillaris. By choosing the threshold of 26.2, the formula (-0.447×F1ch+75.82×VDdp) was the best model to differentiate the vasculitis group from the control group with an area under the curve (AUC) of 0.979, the sensitivity of 98% and specificity of 92.3%. (F1ch: flow in the central 1mm-radius-circle of the choriocapillaris, and VDdp: vascular density of parafoveal in the deep capillary network). Conclusion: In patients with vasculitis, especially in the cases with posterior pole involvement, OCTA showed reduced vascular density and flow in all three capillary layers. OCTA might be a helpful tool to give us additional information about the macular microvasculature changes under inflammatory conditions.