Is OCT Angiography Useful in Neurodegenerative Diseases?

• Published in: Ophthalmic surgery, lasers & imaging Vol. 50; no. 5; pp. 269 - 273
• Main Authors: Grewal, Dilraj S., Fekrat, Sharon, Fine, Howard F.
• Format: Journal Article
• Language: English
• Published: Thorofare, NJ SLACK Incorporated 01.05.2019; Slack, Inc; SLACK INCORPORATED
• Subjects: Aging; Alzheimer's disease; Angiography; Atrophy; Biomarkers; Blood vessels; Brain; Brain research; Central nervous system; Cognitive ability; Correlation analysis; Dementia; Eye (anatomy); Field of view; Fluorescein Angiography - methods; Fractal analysis; Fractal geometry; Fundus Oculi; Humans; Imaging systems; Magnetic resonance imaging; Medical imaging; Nervous system diseases; Neurodegeneration; Neurodegenerative Diseases - diagnosis; Neurological diseases; NMR; Nuclear magnetic resonance; Optical Coherence Tomography; Parkinson's disease; Patients; Reproducibility of Results; Retina; Retina - diagnostic imaging; Thickness; Tomography, Optical Coherence - methods
• ISSN: 2325-8160; 2325-8179; 2325-8179
• DOI: 10.3928/23258160-20190503-02

Not surprisingly, neurodegenerative disorders that affect the brain on a cellular level may be evidenced in the retina. Since optical coherence tomography (OCT) provides in vivo cellular imaging on a near histologic scale with precision at the level of microns, the retina can act as a biomarker for central nervous system disease. Cortical atrophy on magnetic resonance imaging (MRI), as a biomarker for neurodegeneration, can be assessed by quantifying global cortical atrophy, medial temporal lobe atrophy, and parietal cortical atrophy.15,16 Only a few prior studies have evaluated the correlation of OCT parameters with brain MRI, such as association between macular thickness, ganglion cell layer, and RNFL thinning with decreased temporal lobe and occipital lobe volumes and parietal cortical atrophy.17–19 Using OCTA, we looked at 30 eyes of 16 patients (six MCI, 10 AD) and found that the inferolateral ventricle volume inversely correlated with the 6-mm circle and 3-mm circle vessel density in the 6 mm × 6 mm OCTA images. There are significant changes in the retinal periphery, both in terms of changes in retinal blood vessels as measured by the fractal dimension as well as presence of peripheral drusen, which are beyond the field of view of current OCTA systems.21 Koronyo et al. reported that retinal Aβ plaque mirrored brain pathology, and retinal deposits often occurred in the peripheral retina.10 They demonstrated the ability to image retinal amyloid deposits with a modified scanning laser ophthalmoscope and were able to construct a retinal amyloid index, which was about two-fold higher in patients with AD versus controls. Jiang et al. have reported differences using fractal analysis on OCTA superficial and deep capillary plexus between patients with AD and control subjects.25 Conclusions Although current studies do support that retinal microvasculature deficits can be recognized by OCTA in persons with AD, MCI, and PD, prospective, longitudinal studies with larger sample sizes are needed to obtain statistically reliable associations in order to determine the clinical specificity of OCTA measures as useful retinal biomarkers for the early detection of these neurodegenerative diseases.