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Subfoveal choroidal thickness and choroidal vascularity index on spectral‐domain optical coherence tomography in Alzheimer’s disease
Author(s) -
Robbins Cason B,
Grewal Dilraj,
Powers James H,
Thompson Atalie C,
Polascik Bryce W,
Agrawal Rupesh,
Fekrat Sharon
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.042040
Subject(s) - choroid , vascularity , medicine , optical coherence tomography , ophthalmology , retinal , visual acuity , radiology , retina , psychology , neuroscience
Background The involvement of the retina and its vasculature has previously been demonstrated in Alzheimer’s disease (AD). Choroidal parameters such as choroidal thickness (CT) and choroidal vascularity index (CVI) as measured on spectral‐domain optical coherence tomography (SD‐OCT) have the potential to be used as non‐invasive biomarkers for Alzheimer’s disease. Method SD‐OCT imaging of 42 participants with AD, 40 with mild cognitive impairment (MCI), and 139 cognitively healthy controls was obtained in a cross‐sectional study (NCT03233646). Exclusion criteria included diabetes, glaucoma, other non‐AD dementias, and any known vitreoretinal pathology. Subfoveal choroidal thickness (CT) was manually measured by two masked graders, with a third grader used as a tie‐breaker for any measurement discrepancy. Total choroid area and luminal area were calculated by automated image binarization techniques. Choroidal vascularity index (CVI) was measured as the ratio of luminal area to total choroid area. Generalized estimating equations were used to assess the difference in parameters between AD, MCI, and controls in univariable and multivariable analyses. Result Choroidal thickness (p = 0.009), total choroid area (p = 0.02), and luminal area (p = 0.02) were significantly less in AD versus controls in univariable but not in multivariable analysis after controlling for age, sex, and logMAR visual acuity. Choroidal vascularity index was not significantly different between individuals with AD and controls and was significantly different between individuals with MCI and controls only in univariable analysis (p = 0.04). However, CVI was significantly less in AD versus MCI in both univariable and multivariable analyses (p = 0.01). Conclusion Subfoveal choroidal thickness may not be associated with AD independent of aging. However, the choroidal vascularity index was less in AD compared to MCI, suggesting decreased vascularity of the subfoveal choroid in these patients. CVI may be useful as an adjunctive biomarker for the diagnosis of AD.