1. Articles in category: Neurology

    1-24 of 857 1 2 3 4 ... 34 35 36 »
    1. Optical Coherence Tomography Angiography in Neurodegenerative Diseases: A Review

      Optical Coherence Tomography Angiography in Neurodegenerative Diseases: A Review

      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 ...

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    2. Early disability in ambulatory patients with multiple sclerosis: optical coherence tomography versus visual evoked potentials, a comparative study

      Early disability in ambulatory patients with multiple sclerosis: optical coherence tomography versus visual evoked potentials, a comparative study

      Background Multiple sclerosis (MS) is a common cause of neurological disabilities in adults and commonly affects the visual pathway. The objective of this study is to assess and compare the sensitivity of visual evoked potentials (VEP) and optical coherence tomography (OCT) as measures of early disability in ambulatory patients with MS. Methods Forty-four patients with MS with Expanded Disability Status Scale (EDSS) of ≤ 4.5 (ambulatory patients) and 14 healthy controls participated in this study. Patients were classified into 3 groups according to EDSS. Patients with EDSS of 0–1.5 formed the “No disability,” patients with EDSS of 2 ...

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    3. Improved Diagnostic Imaging of Brain Tumors by Multimodal Microscopy and Deep Learning

      Improved Diagnostic Imaging of Brain Tumors by Multimodal Microscopy and Deep Learning

      Fluorescence-guided surgery is a state-of-the-art approach for intraoperative imaging during neurosurgical removal of tumor tissue. While the visualization of high-grade gliomas is reliable, lower grade glioma often lack visible fluorescence signals. Here, we present a hybrid prototype combining visible light optical coherence microscopy (OCM) and high-resolution fluorescence imaging for assessment of brain tumor samples acquired by 5-aminolevulinic acid (5-ALA) fluorescence-guided surgery. OCM provides high-resolution information of the inherent tissue scattering and absorption properties of tissue. We here explore quantitative attenuation coefficients derived from volumetric OCM intensity data and quantitative high-resolution 5-ALA fluorescence as potential biomarkers for tissue malignancy including otherwise ...

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    4. Measurement of Choroid Thickness Using Optical Coherence Tomography to Monitor Intracranial Pressure in an Idiopathic Cranial Hypertension Model

      Measurement of Choroid Thickness Using Optical Coherence Tomography to Monitor Intracranial Pressure in an Idiopathic Cranial Hypertension Model

      Background: Idiopathic intracranial hypertension (IIH) is a condition with increased intracranial pressure (ICP) without mass lesion or a known etiology with normal cerebrospinal fluid (CSF) composition. With optical coherence tomography (OCT), which is a noninvasive imaging technique, cross-sectional scans of the retina, choroid, and optic nerve head can be obtained with a resolution that is close to histological resolution. Aim: The study aimed to evaluate the efficacy of OCT in providing practical and sensitive measurements to follow-up patients with IIH. Materials and Methods: This retrospective study included 22 patients with IIH and 22 healthy controls. OCT was used to measure ...

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    5. Optical Coherence Tomography Angiography for Mapping Cerebral Microvasculature Based on Normalized Differentiation Analysis

      Optical Coherence Tomography Angiography for Mapping Cerebral Microvasculature Based on Normalized Differentiation Analysis

      Optical coherence tomography angiography (OCTA) is a label‐free, noninvasive biomedical imaging modality for mapping microvascular networks and quantifying blood flow velocities in vivo . Simple computation and fast processing are critical for the OCTA in some applications. Herein, we report on a normalized differentiation method for mapping cerebral microvasculature with the advantages of simple analysis and high image quality, benefitting from computation of differentiation and characteristics of normalization. Normalized differentiation values are validated to have a nearly linear relationship with flow velocities in a range using a flow phantom. The measurements in a rat cerebral cortex show that the OCTA ...

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    6. Optical coherence tomography in adult adrenoleukodystrophy: a cross-sectional and longitudinal study

      Optical coherence tomography in adult adrenoleukodystrophy: a cross-sectional and longitudinal study

      Background Adrenoleukodystrophy (ALD) encompasses different neurological phenotypes, ranging from the most severe cerebral forms (C-ALD) to the less severe adrenomyeloneuropathy (AMN). As visual system can be varyingly involved, we aimed at exploring whether optical coherence tomography (OCT) may detect retinal abnormalities and their longitudinal changes in adult ALD patients. Methods In this cross-sectional and longitudinal study, we measured the thicknesses of peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell complex (mGCC), and segmented inner and outer macula at baseline and their changes over time in 11 symptomatic adult ALD males and 10 age- and sex-matched healthy controls. Statistical analyses ...

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    7. University of Houston Receives a 2020 NIH Grant for Biomechanics of Neural Tube Development using Brillouin-OCT Multimodality

      University of Houston Receives a 2020 NIH Grant for Biomechanics of Neural Tube Development using Brillouin-OCT Multimodality

      University of Houston Receives a 2020 NIH Grant for $633,348 for Biomechanics of Neural Tube Development using Brillouin-OCT Multimodality. The principal investigator is Kirill Larin. Below is a summary of the proposed work. The objective of this proposal is to develop a non-contact, all-optical imaging technology to map elastic moduli and forces involved in critical aspects of embryonic development with high 3D resolution. The proposed technology is based on combined Brillouin spectroscopy and Optical Coherence Tomography (OCT), which will be used to gain fundamental understanding of biomechanical factors involved during neural tube closure (NTC) in normal and pathological cases ...

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    8. Investigating the Effect of Ocrelizumab in African Americans and Caucasians With Relapsing Multiple Sclerosis

      Investigating the Effect of Ocrelizumab in African Americans and Caucasians With Relapsing Multiple Sclerosis

      Multiple sclerosis (MS) is a disease of the central nervous system (CNS). Several lines of evidence suggest that MS is an autoimmune disease with both T and B-cell activity leading to CNS inflammation which results in demyelinating injury. Ocrelizumab was FDA approved in March 2017 for relapsing remitting (RRMS) and primary progressive multiple sclerosis (PPMS) by depleting B cells. It has shown to be effective in reducing the annualized relapse rate, decreasing disability progression, and reducing the number of new and active MRI brain lesions. Previous research studies have reported a more aggressive course in African Americans with MS, more ...

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      Mentions: FDA
    9. Optical coherence tomography measures correlate with brain and spinal cord atrophy and multiple sclerosis disease‐related disability

      Optical coherence tomography measures correlate with brain and spinal cord atrophy and multiple sclerosis disease‐related disability

      ackground Both, optical coherence tomography (OCT) and MRI volumetric measures have been postulated as potential biomarkers of MS related disability. Objective To investigate the association between OCT and brain volume (BV) and spinal cord area (SCA) parameters in relapsing MS patients, and to assess their independent associations with disability. Methods Cross‐sectional analysis of 90 MS patients that underwent OCT and MRI exams. Values of peripapillary retinal nerve fibre layer (pRNFL), ganglion cell‐inner plexiform layer (GCIPL), and inner nuclear layer (INL) of eyes without previous ON were obtained. SCA and brain parenchymal, grey and white matter fractions (BPF, GMF ...

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    10. Optical coherence tomography in mild cognitive impairment – systematic review and meta-analysis

      Optical coherence tomography in mild cognitive impairment – systematic review and meta-analysis

      Thinning of retinal layers, measured using optical coherence tomography (OCT), is associated with some neurodegenerative disorders such as established Alzheimer’s disease and multiple sclerosis. The evidence for retinal layer thinning in both mild cognitive impairment (MCI), a precursor of dementia, and delirium, a potential pre-clinical stage of neurodegenerative disorder, is unclear. We performed a systematic review of the associations, in older people, between retinal layer thickness changes (measured using OCT) and delirium or MCI compared to controls (Protocol registration ID (Prospero) CRD42019122165). We did not identify any relevant studies on delirium. This report is therefore a review of retinal ...

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    11. An Update on Imaging in Idiopathic Intracranial Hypertension

      An Update on Imaging in Idiopathic Intracranial Hypertension

      Neuroimaging plays an essential role in the diagnostic workup of idiopathic intracranial hypertension with the aims to exclude secondary causes of elevated intracranial pressure and to identify imaging signs that are commonly observed in this disorder. As a valuable expansion of brain imaging, the imaging of the retina using optical coherence tomography has been of increasing value. In particular, this is the case with the latest devices that allow a more accurate distinction between a reduction in retinal nerve fiber layer thickness due to an improvement of papilledema or due to a worsening caused by optic nerve atrophy. Although optical ...

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    12. Attenuated Visual Function in Patients with Major Depressive Disorder

      Attenuated Visual Function in Patients with Major Depressive Disorder

      Background: We sought to investigate visual function, primarily, and structural changes in retinal ganglion cells, secondarily, in patients with major depressive disorder. Methods: A total of 50 normal participants and 49 patients with major depressive disorder were included in this cross-sectional study. The participants underwent 24–2 standard automated perimetry and spectral-domain optical coherence tomography. Results: The pattern standard deviation (PSD) in the visual field test was higher in the major depressive disorder patients than in the normal control subjects ( P = 0.017). The patients with major depressive disorder showed reduced minimum ganglion cell–inner plexiform layer (GCIPL) thickness relative ...

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    13. MRI-based brain volumetry and retinal optical coherence tomography as the biomarkers of outcome in acute methanol poisoning

      MRI-based brain volumetry and retinal optical coherence tomography as the biomarkers of outcome in acute methanol poisoning

      Background Basal ganglia lesions are typical findings on magnetic resonance imaging (MRI) of the brain in survivors of acute methanol poisoning. However, no data are available on the association between the magnitude of damaged brain regions, serum concentrations of markers of acute methanol toxicity, oxidative stress, neuroinflammation, and the rate of retinal nerve ganglion cell loss. Objectives To investigate the association between MRI-based volumetry of the basal ganglia, retinal nerve fibre layer (RNFL) thickness and prognostic laboratory markers of outcomes in acute methanol poisoning. Methods MRI-based volumetry of putamen, nucleus caudatus and globus pallidus was performed and compared with laboratory ...

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    14. Quantitative Assessment of Optical Coherence Tomography Angiography Algorithms for Neuroimaging

      Quantitative Assessment of Optical Coherence Tomography Angiography Algorithms for Neuroimaging

      Optical coherence tomography (OCT) angiography can noninvasively map microvascular networks and quantify blood flow in a cerebral cortex with a resolution of 1–10 μm and a penetration depth of 2–3 mm incorporating OCT signals and angiography algorithms. Different angiography algorithms have been developed in recent years; however, the performance of the algorithms has not been assessed quantitatively for neuroimaging applications. In this paper, we developed four metrics including vascular connectivity, contrast‐to‐noise ratio (CNR), signal‐to‐noise ratio (SNR) and processing time to quantitatively assess the performance of OCT angiography algorithms in image quality and computation speed ...

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      Mentions: Jiang Zhu
    15. Optical coherence tomography angiography as a potential screening tool for cerebral small vessel diseases

      Optical coherence tomography angiography as a potential screening tool for cerebral small vessel diseases

      Background The retina and the brain share anatomic, embryologic, and physiologic characteristics. Therefore, retinal imaging in patients with brain disorders has been of significant interest. Using optical coherence tomography angiography (OCTA), a novel quantitative method of measuring retinal vasculature, we aimed to evaluate radial peripapillary capillary (RPC) network density and retinal nerve fiber layer (RNFL) thickness in cognitively impaired patients and determine their association with brain imaging markers. Methods In this prospective cross-sectional study, a total of 69 patients (138 eyes) including 29 patients with amyloid-positive Alzheimer’s disease-related cognitive impairment (ADCI), 25 patients with subcortical vascular cognitive impairment (SVCI ...

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    16. ASSESSING TERATOGEN-INDUCED CHANGES IN MURINE FETAL BRAIN VASCULATURE USING IN UTERO OPTICAL COHERENCE TOMOGRAPHY (Thesis)

      ASSESSING TERATOGEN-INDUCED CHANGES IN MURINE FETAL BRAIN VASCULATURE USING IN UTERO OPTICAL COHERENCE TOMOGRAPHY (Thesis)

      This dissertation reports the use of in utero optical coherence tomography to evaluate changes in vasculature in a developing murine fetal brain caused due to prenatal exposure to teratogens. Embryogenesis is a highly complex process that is extremely vulnerable to external factors. Proper visualization of embryonic development is crucial to understand the basic physiological processes and identify defects if any. This dissertation is divided into two major sections: 1) assessing teratogen induced changes in the murine fetal brain vasculature during the second trimester equivalent period (chapters 2-4) and 2) combining optical coherence tomography with Brillouin microscopy to image and evaluate ...

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    17. Retinal optical coherence tomography for children with cerebral palsy

      Retinal optical coherence tomography for children with cerebral palsy

      Many individuals with cerebral palsy (CP) also have damage to their central visual pathways. These comprise the right and left optic tract (from optic chiasm to lateral geniculate nucleus [LGN]); the optic radiations from LGN to the occipital cortex; and several other networks that integrate the visual information with motor, attentional, and cognitive centres. Topographic information about which part of the retina (hence where in the visual field) is stimulated by light is preserved throughout the optic nerve and the central visual pathways. Jacobson et al. describe how regional variations in retinal layer thickness can therefore reflect focal central visual ...

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    18. Predictive value of optical coherence tomography, multifocal visual evoked potentials, and full-field visual evoked potentials of the fellow, non-symptomatic eye for subsequent multiple sclerosis development in patients with acute optic neuritis

      Predictive value of optical coherence tomography, multifocal visual evoked potentials, and full-field visual evoked potentials of the fellow, non-symptomatic eye for subsequent multiple sclerosis development in patients with acute optic neuritis

      Background: Diagnosis of multiple sclerosis (MS) may sometimes be ascertained at the time of optic neuritis (ON) but other times require the advent of new disease activity. Objectives: The aim of this study was to examine the predictive value of optical coherence tomography (OCT) and visual evoked potential (VEP) measurements of the non-symptomatic, fellow eye of ON patients, for conversion to MS. Methods: This is a prospective cohort study in patients with acute ON. OCT thickness measurements of peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell layer–inner plexiform layer (GCLIPL), and multifocal (mf) VEP and full-field (ff ...

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    19. Accuracy of optical coherence tomography imaging in assessing aneurysmal remnants after flow diversion

      Accuracy of optical coherence tomography imaging in assessing aneurysmal remnants after flow diversion

      Background Optical coherence tomography (OCT) is an ultra-high resolution real-time intravascular imaging method that is gaining interest in cerebrovascular applications. Objective To compare, in a rabbit elastase aneurysm model, digital subtraction angiography (DSA) and OCT as diagnostic tools for the assessment of aneurysmal remnants and baseline characteristics of aneurysms after flow diverter (FD) implantation. Methods With Institutional Animal Care and Use Committee approval, saccular aneurysms were created in 28 rabbits and treated with Derivo FDs. DSA was performed before, and immediately after, stent implantation. As a follow-up, DSA and OCT were performed 28 days after device implantation. Results DSA and ...

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    20. Optical coherence tomography angiography in nonarteritic anterior ischemic optic neuropathy due to optic nerve head drusen

      Optical coherence tomography angiography in nonarteritic anterior ischemic optic neuropathy due to optic nerve head drusen

      Optic nerve head drusen (ONHD) are typically benign hyaline and calcified concretions located within the optic nerve. Initially asymptomatic, they can increase slowly in size and number over time, and they can cause mechanical stress at the axons of the optic nerve and progressively lead to a loss of the visual field and papillary vascular changes. Here, we reported a rare case of a young patient with bilateral ONHD complicated by a nonarteritic anterior ischemic optic neuropathy (NAION) in the right eye. The aim of this case was to evaluate, using optical coherence tomography angiography (OCTA), the vascular network of ...

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    21. Optical Coherence Tomography Angiography in Neurodegenerative Disorders

      Optical Coherence Tomography Angiography in Neurodegenerative Disorders

      Retinal microcirculation shares similar features with cerebral small blood vessels. Thus, the retina may be considered an accessible ‘window’ to detect the microvascular damage occurring in the setting of neurodegenerative disorders. Optical coherence tomography angiography (OCT-A) is a non-invasive imaging modality providing depth resolved images of blood flow in the retina, choroid, and optic nerve. In this review, we summarize the current literature on the application of OCT-A in glaucoma and central nervous system conditions such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Future directions aiming at evaluating whether OCT-A can be an additional biomarker for the ...

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    22. Longitudinal Monitoring of Flow-Diverting Stent Tissue Coverage After Implant in a Bifurcation Model Using Neurovascular High-Frequency Optical Coherence Tomography

      Longitudinal Monitoring of Flow-Diverting Stent Tissue Coverage After Implant in a Bifurcation Model Using Neurovascular High-Frequency Optical Coherence Tomography

      BACKGROUND Tissue growth over covered branches is a leading cause of delayed thrombotic complications after flow-diverter stenting (FDS). Due to insufficient resolution, no imaging modality is clinically available to monitor this phenomenon. OBJECTIVE To evaluate high-frequency optical coherence tomography (HF-OCT), a novel intravascular imaging modality designed for the cerebrovascular anatomy with a resolution approaching 10 microns, to monitor tissue growth over FDS in an arterial bifurcation model. METHODS FDS were deployed in a rabbit model (n = 6), covering the aortic bifurcation. The animals were divided in different groups, receiving dual antiplatelet therapy (DAPT) (n = 4), aspirin only (n = 1), and ...

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