Spectral-Domain OCT Measurements in Alzheimer’s Disease

Chan, Victor T.T.; Sun, Zihan; Tang, Shumin; Chen, Li Jia; Wong, Adrian; Tham, Clement C.; Wong, Tien Yin; Chen, Christopher; Ikram, M. Kamran; Whitson, Heather E.; Lad, Eleonora M.; Mok, Vincent Chung Tong; Cheung, Carol Y.

doi:10.1016/j.ophtha.2018.08.009

Cited by 266 publications

(301 citation statements)

References 181 publications

(249 reference statements)

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“…These results provide an in vivo validation for that which was previously observed ex vivo by Perez et al 44 In future studies, the inner and outer retina could be subdivided further to quantify individual layer thickness. Since RNFL thinning occurs in AD patients, 28,29 it may also be interesting to quantify the RNFL thickness alone in this mouse model. However, quantifying the RNFL thickness in mice using OCT is difficult, as the peripapillary thickness of the healthy RNFL is only approximately 20 µm, 74 and is interrupted by blood vessels and ganglion cells.…”

Section: Cortical Amyloid Beta Plaque Loadmentioning

confidence: 99%

“…26,27 Retinal layer thinning, particularly in the retinal nerve fiber layer (RNFL), is also present in the retina of AD patients. 28,29 However looking forward to a marker for diagnosis, RNFL thinning is not specific to AD and it is not only associated with other diseases such as glaucoma 30 and Parkinson's disease, 31 but also more generally with increasing age. 32 With many contradictory observations, it is clear that there is still a great deal of research to be performed in order to fully understand the effects of AD on the retina.…”

Section: Introductionmentioning

confidence: 99%

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Retinal analysis of a mouse model of Alzheimer’s disease with multicontrast optical coherence tomography

et al. 2020

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Recent Alzheimer's disease (AD) patient studies have focused on retinal analysis, as the retina is the only part of the central nervous system which can be imaged non-invasively by optical methods. However as this is a relatively new approach, the occurrence and role of pathological features such as retinal layer thinning, extracellular amyloid beta (Aβ) accumulation and vascular changes is still debated. Animal models of AD are therefore often used in attempts to understand the disease. In this work, both eyes of 24 APP/PS1 transgenic mice (age: 45-104 weeks) and 15 age-matched wildtype littermates were imaged by a custom-built multi-contrast optical coherence tomography (OCT) system. The system provided a combination of standard reflectivity data, polarization-sensitive data and OCT angiograms. This tri-fold contrast provided qualitative and quantitative information on retinal layer thickness and structure, presence of hyper-reflective foci, phase retardation abnormalities and retinal vasculature. While abnormal structural properties and phase retardation signals were observed in the retinas, the observations were very similar in transgenic and control mice. At the end of the experiment, retinas and brains were harvested from a subset of the mice (14 transgenic, 7 age-matched control) in order to compare the in vivo results to histological analysis, and to quantify the cortical Aβ plaque load. arXiv:1909.08466v2 [physics.med-ph]

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Section: Cortical Amyloid Beta Plaque Loadmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Retinal analysis of a mouse model of Alzheimer’s disease with multicontrast optical coherence tomography

et al. 2020

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“…Beyond ophthalmology, there is also potential for SD‐OCT retinal images to provide biomarkers for disease. In particular, multiple studies have noted the potential of SD‐OCT to provide a biomarker for neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and frontotemporal degeneration (FTD) . Studies have also applied SD‐OCT to evaluate retinal thickness associations with cognitive decline, particularly in large data sets .…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Iowa Reference Algorithm to the Heidelberg Spectralis optical coherence tomography segmentation algorithm

Sun

McGeehan

Firn

et al. 2020

Journal of Biophotonics

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For spectral-domain optical coherence tomography (SD-OCT) studies of neurodegeneration, it is important to understand how segmentation algorithms differ in retinal layer thickness measurements, segmentation error locations and the impact of manual correction. Using macular SD-OCT images of frontotemporal degeneration patients and controls, we compare the individual and aggregate retinal layer thickness measurements provided by two commonly used algorithms, the Iowa Reference Algorithm and Heidelberg Spectralis, with manual correction of significant segmentation errors. We demonstrate small differences of most retinal layer thickness measurements between these algorithms. Outer sectors of the Early Treatment Diabetic Retinopathy Study grid require a greater percent of eyes to be corrected than inner sectors of the retinal nerve fiber layer (RNFL). Manual corrections affect thickness measurements mildly, resulting in at most a 5% change in RNFL thickness. Our findings can inform researchers how to best use different segmentation algorithms when comparing retinal layer thicknesses. K E Y W O R D S frontotemporal degeneration, Iowa Reference Algorithm, optical coherence tomography, retinal layer thickness, segmentation algorithms, Spectralis

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“…Furthermore, OCTA is capable of measuring retinal capillary beds at distinct depths, separating the super cial capillary plexuses (SCP) and deep capillary plexuses (DCP), each re ecting the metabolic demand of particular neuronal layers. [5] In AD, the tissue of interest is the inner retinal layer, as re ected by the loss of retinal ganglion cells, [7,8] thinning of the retinal nerve bre layer thickness and ganglion cell layer thickness, [9] and deposition of β-amyloid (Aβ) plaques. [10] While there are a few OCTA studies investigating AD, there have been mixed conclusions.…”

Section: Introductionmentioning

confidence: 99%

Retinal Microvascular Alterations in Alzheimer’s Disease and Mild Cognitive Impairment

Chua

et al. 2020

Preprint

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Background: The retina and brain share many neuronal and vasculature characteristics developmentally and potential biomarkers may be present in the retina. We investigated the retinal microvasculature in Alzheimer’s disease (AD) and mild cognitive impairment (MCI) using optical coherence tomography angiography (OCTA).Methods: In this cross-sectional study, 24 AD participants, 37 MCI participants, and 29 controls were diagnosed according to internationally accepted criteria. OCTA images of the superficial and deep capillary plexus (SCP, DCP) of the retinal microvasculature were obtained using a commercial OCTA system (Zeiss Cirrus HD-5000 with AngioPlex, Carl Zeiss Meditec, Dublin, CA). The main outcome measures were vessel density (VD) and fractal dimension (FD) in the SCP and DCP within a 2.5-mm ring around the fovea were compared between groups. Perfusion density of large vessels and foveal avascular zone (FAZ) area were additional outcome parameters.Results: Age, gender and race did not differ among groups. However, there was a significant difference in diabetes status (P=0.039), and systolic blood pressure (P=0.008) among the groups. After adjusting for confounders, AD participants showed significantly decreased VD in SCP and DCP (P = 0.005 and P = 0.016, respectively) and decreased FD in SCP (P = 0.008), compared to controls. MCI participants showed significantly decreased VD and FD only in SCP (P = 0.005 and P < 0.001, respectively) and not the DCP (P > 0.05) compared with controls. There was no difference in the OCTA variables between AD and MCI (P > 0.05). Perfusion density of large vessels and FAZ area did not differ significantly between groups (P > 0.05).Conclusions and relevance: Eyes of patients with AD have significantly reduced macular VD in both plexuses whereas MCI participants only showed reduction in the superficial plexus. Changes in the retinal microvasculature and capillary network may mirror small vessel cerebrovascular changes in AD.

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Spectral-Domain OCT Measurements in Alzheimer’s Disease

Abstract: Our results confirmed the associations between retinal measurements of SD OCT and AD, highlighting the potential usefulness of SD OCT measurements as biomarkers of AD.

Cited by 266 publications

References 181 publications

Retinal analysis of a mouse model of Alzheimer’s disease with multicontrast optical coherence tomography

Retinal analysis of a mouse model of Alzheimer’s disease with multicontrast optical coherence tomography

Comparison of the Iowa Reference Algorithm to the Heidelberg Spectralis optical coherence tomography segmentation algorithm

Retinal Microvascular Alterations in Alzheimer’s Disease and Mild Cognitive Impairment

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