Optical coherence tomography angiography in cognitively impaired patients: Vascular and neurodegenerative perspectives

Abstract

AbstractBackgroundVascular and neuronal changes in the retina may reflect cerebral small vessel disease (CSVD) and neurodegeneration in the brain. We aimed to compare radial peripapillary capillary (RPC) network density and RNFL thickness between diagnostic groups using optical coherence tomography angiography (OCTA) imaging. Then, we evaluated whether the RPC network density correlated with CSVD markers and whether RNFL correlated with Aβ or brain cortical thickness.MethodIn this prospective, cross‐sectional, observational study, subjects were recruited from February 2018 to March 2019. Retinal vascular [Capillary density (CD) of the radial peripapillary capillary (RPC) network] and neurodegeneration markers [retinal nerve fiber layer (RNFL) thickness at four quadrants] were measured using optical coherence tomography (OCT) and OCT angiography (OCTA) imaging. Brain vascular (CSVD score), and neurodegeneration markers [brain cortical thickness] were assessed using 3D brain magnetic resonance imaging. We compared CD and RNFL thickness between ADCI, SVCI, and CN group. Then, we evaluated correlation between retinal imaging markers (CD and RNFL) and brain imaging markers (CSVD score and cortical thickness)ResultThe mean (SD) age of total 60 participants was 70.3 (9.0) years and 21 (35%) of them were male. The SVCI group showed lower CD in the temporal quadrant of RPC network compared to the CN group (mean (sd), 42.34 (6.29) vs 48.45 (7.08); p = 0.002), and lower CD in the superior quadrant of RPC network (mean (sd), 60.14 (6.42) vs 64.15 (6.39); p = 0.021) compared with the ADCI group. The CD was negatively correlated with CSVD score in the superior (regression coefficient, ‐0.050; 95% CI, ‐0.083 to 0.017; p=0.004) and temporal (regression coefficient, ‐0.042; 95% CI, ‐0.070 to ‐0.014; p=0.004) quadrants of the RPC network. RNFL thickness did not differ among the groups nor did it correlate with cortical thickness.ConclusionThe importance of the CD of the RPC network rather than RNFL thicknesses should be highlighted in evaluating cerebral pathology. Moreover, noninvasive and rapid acquisition of OCTA images has the potential to be used as a peripheral imaging tool to screen for the degree of CSVD.