Is OCT Angiography Useful in Neurodegenerative Diseases?

Grewal, Dilraj S.; Fine, Howard F; Fekrat, Sharon

doi:10.3928/23258160-20190503-02

Cited by 6 publications

(13 citation statements)

References 25 publications

(24 reference statements)

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“…For example, the retinal nerve fiber layer (RNFL) is thinner, the retinal volume is reduced, and the choroidal thickness is reduced in patients with mild cognitive impairment (MCI) and AD compared to cognitively normal (CN) controls [25][26][27][28][29][30][31][32][33][34][35][36][37][38]. A newer and more sophisticated version of the OCT, the optical coherence tomography angiography (OCTA), has shown significant changes to the superficial and deep capillary vascular plexus of the macula and changes to the foveal avascular zone in those with cognitive dysfunction and AD compared to CN controls [39][40][41][42][43][44][45][46][47][48][49]. However, data obtained by OCT/OCTA, while promising, have shown conflicting results and can be confounded by the presence of co-existing eye disease and systemic diseases, such as diabetes, as well as variations in cell layer measurements by different automated platforms [50].…”

Section: Discussionmentioning

confidence: 99%

Neurofilament light chain in the vitreous humor of the eye

et al. 2020

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Background Neurofilament light chain (NfL) is a promising biomarker of neurodegeneration in the cerebrospinal fluid and blood. This study investigated the presence of NfL in the vitreous humor and its associations with amyloid beta, tau, inflammatory cytokines and vascular proteins, apolipoprotein E (APOE) genotypes, Mini-Mental State Examination (MMSE) scores, systemic disease, and ophthalmic diseases. Methods This is a single-site, prospective, cross-sectional cohort study. Undiluted vitreous fluid (0.5–1.0 mL) was aspirated during vitrectomy, and whole blood was drawn for APOE genotyping. NfL, amyloid beta (Aβ), total Tau (t-Tau), phosphorylated Tau (p-Tau181), inflammatory cytokines, chemokines, and vascular proteins in the vitreous were quantitatively measured by immunoassay. The main outcome measures were the detection of NfL levels in the vitreous humor and its associations with the aforementioned proteins. Linear regression was used to test the associations of NfL with other proteins, APOE genotypes, MMSE scores, and ophthalmic and systemic diseases after adjustment for age, sex, education level, and other eye diseases. Results NfL was detected in all 77 vitreous samples. NfL was not found to be associated with ophthalmic conditions, APOE genotypes, MMSE scores, or systemic disease (p > 0.05). NfL levels were positively associated with increased vitreous levels of Aβ40 (p = 7.7 × 10−5), Aβ42 (p = 2.8 × 10−4), and t-tau (p = 5.5 × 10−7), but not with p-tau181 (p = 0.53). NfL also had significant associations with inflammatory cytokines such as interleukin-15 (IL-15, p = 5.3 × 10−4), IL-16 (p = 2.2 × 10−4), monocyte chemoattractant protein-1 (MCP1, p = 4.1 × 10−4), and vascular proteins such as vascular endothelial growth factor receptor-1 (VEGFR1, p = 2.9 × 10−6), Vegf-C (p = 8.6 × 10−6), vascular cell adhesion molecule-1 (VCAM-1, p = 5.0 × 10−4), Tie-2 (p = 6.3 × 10−4), and intracellular adhesion molecular-1 (ICAM-1, p = 1.6 × 10−4). Conclusion NfL is detectable in the vitreous humor of the eye and significantly associated with amyloid beta, t-tau, and select inflammatory and vascular proteins in the vitreous. Additionally, NfL was not associated with patients’ clinical eye condition. Our results serve as a foundation for further investigation of NfL in the ocular fluids to inform us about the potential utility of its presence in the eye.

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Section: Discussionmentioning

confidence: 99%

Neurofilament light chain in the vitreous humor of the eye

et al. 2020

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“…Since OCT-A was introduced in 2015, the current data available about its applications stem from studies that contain small sample sizes and this limits the level of evidence and the validity of the findings. 123 There is still a significant learning curve in terms of interpretation and there is no unanimous protocol as to which parameters should be taken into account and this may lead to falsepositive or -negative results that affect the validity of the findings and yield contradictory results among different study groups. 117 Another important limitation is that many of these neurodegenerative disorders can affect the mental capacity of such patients and subsequently their cooperation when OCT-A images are obtained.…”

Section: Limitations In the Use Of Oct-amentioning

confidence: 99%

“…As a result, this may lead to poor quality images that can lead to inaccurate interpretation due to motion artifacts. 123 Since OCT-A demands high levels of patient cooperation and attentiveness, it may not be quite useful imaging tools in children due to their very short attention span. 117 Furthermore, the commercially available OCT-A devices are not able to provide a wide field of view of the vasculature of the peripheral retina and the views are very limited to the posterior pole.…”

Section: Limitations In the Use Of Oct-amentioning

confidence: 99%

“…117 Furthermore, the commercially available OCT-A devices are not able to provide a wide field of view of the vasculature of the peripheral retina and the views are very limited to the posterior pole. 123 This prevents us from studying meticulously the whole retinal periphery and this has also led to numerous studies that are confined to the macular and optic nerve head regions so far. In addition, not all amount of light can be transmitted through the erythrocytes and this mainly affects the precise depiction of the choroidal vasculature, since the melanosomes of the retinal pigment epithelium not only absorb but also induce light scattering.…”

Section: Limitations In the Use Of Oct-amentioning

confidence: 99%

“…The OCT-A findings in retinal vascular disease have a significant amount of overlapping with the retinal changes induced by the neurodegenerative disorders and therefore it is quite challenging to describe accurately the real extent of the contributions of each pathological entity due to substandard segmentation carried out by the current OCT-A software available. 123 In the same context, other macular or optic nerve lesions, such as epiretinal membranes or myelinated nerve fiber layers can obscure the images obtained by the OCT-A devices. 117,123 Finally, the size of the retinal capillaries varies from 5μm to 10 μm.…”

Section: Limitations In the Use Of Oct-amentioning

confidence: 99%

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<p>Optical Coherence Tomography Angiography in Neurodegenerative Diseases: A Review</p>

Tsokolas

Tsaousis

Diakonis

et al. 2020

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Background: Optical coherence tomography angiography (OCT-A) has emerged as a novel, fast, safe and non-invasive imaging technique of analyzing the retinal and choroidal microvasculature in vivo. OCT-A captures multiple sequential B-scans performed repeatedly over a specific retinal area at high speed, thus enabling the composition of a vascular map with areas of contrast change (high flow zones) and areas of steady contrast (slow or no flow zones). It therefore provides unique insight into the exact retinal or choroidal layer and location at which abnormal blood flow develops. OCTA has evolved into a useful tool for understanding a number of retinal pathologies such as diabetic retinopathy, age-related macular degeneration, central serous chorioretinopathy, vascular occlusions, macular telangiectasia and choroidal neovascular membranes of other causes. OCT-A technology is also increasingly being used in the evaluation of optic disc perfusion and has been suggested as a valuable tool in the early detection of glaucomatous damage and monitoring progression. Objective: To review the existing literature on the applications of optical coherence tomography angiography in neurodegenerative diseases. Summary: A meticulous literature was performed until the present day. Google Scholar, PubMed, Mendeley search engines were used for this purpose. We used 123 published manuscripts as our references. OCT-A has been utilized so far to describe abnormalities in multiple sclerosis (MS), Alzheimer's disease, arteritic and non-arteritic optic neuropathy (AION and NAION), Leber's hereditary optic neuropathy (LHON) papilloedema, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis (ALS), Wolfram syndrome, migraines, lesions of the visual pathway and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). It appears that OCT-A findings correlate quite well with the severity of the aforementioned diseases. However, OCT-A has its own limitations, namely its lack of wide-field view of the peripheral retina and the inaccurate interpretation due to motion artifacts in uncooperative groups of patients (e.g. children). Larger prospective longitudinal studies will need to be conducted in order to eliminate the aforementioned limitations.

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