1. Articles in category: Neurology

    1-24 of 595 1 2 3 4 ... 23 24 25 »
    1. A Comparative Study between Fundus Imaging and Optical Coherence Tomography for the Early Diagnosis of Alzheimer’s Disease

      A Comparative Study between Fundus Imaging and Optical Coherence Tomography for the Early Diagnosis of Alzheimer’s Disease

      Alzheimer’s disease (AD) is a neurodegenerative condition as well as changes in retina region that leads to permanent memory loss. AD is presently creating lot of problems in care taking. There are lot of tests and imaging modalities to be performed for an effective diagnosis of the disease. The most popular of them are Magnetic Resonance Imaging, Positron Emission Tomography and Single Photon Emission CT Scanning. They can provide valuable information regarding the changes in brain regions for diagnosing AD. But the detailed study made on AD suggests that there are some variations on the retina region of the ...

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    2. 3D topology of orientation columns in visual cortex revealed by functional optical coherence tomography

      3D topology of orientation columns in visual cortex revealed by functional optical coherence tomography

      Orientation tuning is a canonical neuronal response property of 6-layer visual cortex that is encoded in pinwheel structures with center orientation singularities. Optical imaging of intrinsic signals enables us to map these surface 2D structures, while lack of appropriate techniques has not allowed us to visualize depth structures of orientation coding. Here, we performed functional optical coherence tomography (fOCT), a technique capable of acquiring 3D map of the intrinsic signals, to study the topology of orientation coding inside the cat visual cortex. With this technique, for the first time, we visualized columnar assemblies in orientation coding that had been predicted ...

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    3. Comparing three-dimensional serial optical coherence tomography histology to MRI imaging in the entire mouse brain

      Comparing three-dimensional serial optical coherence tomography histology to MRI imaging in the entire mouse brain

      An automated serial histology setup combining optical coherence tomography (OCT) imaging with vibratome sectioning was used to image eight wild type mouse brains. The datasets resulted in thousands of volumetric tiles resolved at a voxel size of ( 4.9 × 4.9 × 6.5 ) μ m 3 (4.9×4.9×6.5)  μm3 stitched back together to give a three-dimensional map of the brain from which a template OCT brain was obtained. To assess deformation caused by tissue sectioning, reconstruction algorithms, and fixation, OCT datasets were compared to both in vivo and ex vivo magnetic resonance imaging (MRI) imaging. The OCT ...

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    4. European Multiple Sclerosis Consortium to use Voxeleron’s Orion for OCT Image Analysis

      European Multiple Sclerosis Consortium to use Voxeleron’s Orion for OCT Image Analysis

      Orion, Voxeleron’s device-independent, optical coherence tomography (OCT) image analysis platform will look for central nervous system damage. Voxeleron is excited to announce their collaborative role in the Sys4MS (Systems for Multiple Sclerosis) multi-center research initiative aimed at developing new tools for personalized management of patients with MS and other complex diseases. Sys4MS focuses on five specific areas: genomics, proteomics, cytomics, imaging and phenotype. The imaging portion, run from the Charité - Universitätsmedizin Berlin’s NeuroCure Clinical Research Center, will use OrionTM to analyze OCT images and help quantify damage to the central nervous system. “Analyzing all scans with the ...

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    5. Cross-Polarization Optical Coherence Tomography in Comparative in vivo and ex vivo Studies of the Optical Properties of Normal and Tumorous Brain Tissues

      Cross-Polarization Optical Coherence Tomography in Comparative in vivo and ex vivo Studies of the Optical Properties of Normal and Tumorous Brain Tissues

      The aim of the study was to provide visual and quantitative evaluation of tumorous and normal brain tissue images obtained by cross-polarization optical coherence tomography (CP OCT) in a comparative in vivo and ex vivo study. Materials and Methods. The CP OCT as a non-damaging noninvasive optical method for tissue structure imaging was used in the study. It enables obtaining volumetric images of 2.4×2.4×1.25 mm 3 in size in real time within a short time of 26 s. The objects were tumorous and normal brain tissues of 12 experimental animals (Wistar rats): 4 — intact, 4 ...

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    6. Optical coherence tomography angiography indicates associations of the retinal vascular network and disease activity in multiple sclerosis

      Optical coherence tomography angiography indicates associations of the retinal vascular network and disease activity in multiple sclerosis

      Background: Patients with multiple sclerosis (MS) and clinically isolated syndrome (CIS) may show alterations of retinal layer architecture as measured by optical coherence tomography. Little is known about changes in the retinal vascular network during MS. Objective: To characterize retinal vessel structures in patients with MS and CIS and to test for associations with MS disease activity. Method: In all, 42 patients with MS or CIS and 50 healthy controls underwent retinal optical coherence tomography angiography (OCT-A) with analysis of the superficial and deep vascular plexuses and the choriocapillaries. We tested OCT-A parameters for associations with retinal layer volumes, history ...

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    7. Evaluating the Effects of Maternal Alcohol Consumption on Murine Fetal Brain Vasculature Using Optical Coherence Tomography

      Evaluating the Effects of Maternal Alcohol Consumption on Murine Fetal Brain Vasculature Using Optical Coherence Tomography

      Prenatal alcohol exposure (PAE) can result in a range of anomalies including brain and behavioral dysfunctions, collectively termed fetal alcohol spectrum disorder (FASD). PAE during the 1 st and 2 nd trimester is common, and research in animal models has documented significant neural developmental deficits associated with PAE during this period. However, little is known about the immediate effects of PAE on fetal brain vasculature. In this study, we used in utero speckle variance optical coherence tomography (SVOCT), a high spatial- and temporal–resolution imaging modality, to evaluate dynamic changes in micro-vasculature of the 2 nd trimester-equivalent murine fetal brain ...

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    8. Application of optical coherence tomography for in vivo monitoring of the meningeal lymphatic vessels during opening of blood–brain barrier: mechanisms of brain clearing

      Application of optical coherence tomography for in vivo monitoring of the meningeal lymphatic vessels during opening of blood–brain barrier: mechanisms of brain clearing

      The meningeal lymphatic vessels were discovered 2 years ago as the drainage system involved in the mechanisms underlying the clearance of waste products from the brain. The blood–brain barrier (BBB) is a gatekeeper that strongly controls the movement of different molecules from the blood into the brain. We know the scenarios during the opening of the BBB, but there is extremely limited information on how the brain clears the substances that cross the BBB. Here, using the model of sound-induced opening of the BBB, we clearly show how the brain clears dextran after it crosses the BBB via the ...

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    9. Optical Coherence Tomography in Optic Nerve Hypoplasia: Correlation With Optic Disc Diameter, Nerve Fiber Layer Thickness, and Visual Function

      Optical Coherence Tomography in Optic Nerve Hypoplasia: Correlation With Optic Disc Diameter, Nerve Fiber Layer Thickness, and Visual Function

      Background: The correlation between optic disc diameters (DDs) with average retinal nerve fiber layer thickness (RNFLT) and visual function in children with optic nerve hypoplasia (ONH) having nystagmus is unknown. Methods: Data were obtained from a retrospective review of 28 children (mean age: 9.4 years; ±5.1). Optic DD was defined as the maximal horizontal opening of Bruch membrane with spectral optical coherence tomography combined with a confocal laser ophthalmoscope. Average RNFLT was obtained from circumpapillary b-scans. RNFLT was also remeasured at eccentricities that were proportionate with DD to rule out potential sampling artifacts. Visual function was assessed by ...

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    10. Advances in Brain Tumor Surgery for Glioblastoma in Adults

      Advances in Brain Tumor Surgery for Glioblastoma in Adults

      Glioblastoma (GBM) is the most common primary intracranial neoplasia, and is characterized by its extremely poor prognosis. Despite maximum surgery, chemotherapy, and radiation, the histological heterogeneity of GBM makes total eradication impossible, due to residual cancer cells invading the parenchyma, which is not otherwise seen in radiographic images. Even with gross total resection, the heterogeneity and the dormant nature of brain tumor initiating cells allow for therapeutic evasion, contributing to its recurrence and malignant progression, and severely impacting survival. Visual delimitation of the tumor’s margins with common surgical techniques is a challenge faced by many surgeons. In an attempt ...

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    11. Patterns of retinal ganglion cell damage in neurodegenerative disorders: parvocellular vs magnocellular degeneration in OCT studies

      Patterns of retinal ganglion cell damage in neurodegenerative disorders: parvocellular vs magnocellular degeneration in OCT studies

      Many neurodegenerative disorders, such as Parkinson’s disease (PD) and Alzheimer’s disease (AD), are characterized by loss of retinal ganglion cells (RGCs) as part of the neurodegenerative process. Optical coherence tomography (OCT) studies demonstrated variable degree of optic atrophy in these diseases. However, the pattern of degenerative changes affecting the optic nerve can be different. In particular, neurodegeneration is more evident for magnocellular RGCs in AD and multiple system atrophy with a pattern resembling glaucoma. Conversely, in PD and Huntington’s disease the parvocellular RGCs are more vulnerable. This latter pattern closely resembles that of mitochondrial optic neuropathies, possibly ...

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    12. Optical coherence tomography indices of structural retinal pathology in schizophrenia

      Optical coherence tomography indices of structural retinal pathology in schizophrenia

      Prior optical coherence tomography (OCT) studies of schizophrenia have identified thinning of retinal layers. However, findings have varied across reports, and most studies have had serious methodological limitations. To address unresolved issues, we determined whether: (1) retinal thinning in schizophrenia occurs independently of comorbid medical conditions that affect the retina; (2) thinning is independent of antipsychotic medication dose; (3) optic nerve parameters are abnormal in schizophrenia; and (4) OCT indices are related to visual and cognitive impairments common in schizophrenia. A total of 32 people with schizophrenia and 32 matched controls participated. Spectral domain OCT generated data on retinal nerve ...

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    13. Optical Coherence Tomography in Alzheimer’s Disease and Other Neurodegenerative Diseases

      Optical Coherence Tomography in Alzheimer’s Disease and Other Neurodegenerative Diseases

      Over the last decade, a surge of evidence has documented various pathological processes in the retina of patients suffering from mild cognitive impairment, Alzheimer’s disease (AD), Parkinson’s disease, and other neurodegenerative diseases. Numerous studies have shown that the retina, a CNS tissue formed as a developmental outgrowth of the brain, is profoundly affected by AD. Harboring the earliest detectable disease-specific signs, amyloid β-protein (Aβ) plaques, the retina of AD patients undergoes substantial ganglion cell degeneration, thinning of the retinal nerve fiber layer (RNFL), and loss of axonal projections in the optic nerve, among other abnormalities. More recent investigations ...

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    14. Optical Coherence Tomography in Patients with Chronic Migraine: Literature Review and Update

      Optical Coherence Tomography in Patients with Chronic Migraine: Literature Review and Update

      Migraine is a chronic disease characterized by unilateral, pulsating, and often moderate-to-severe recurrent episodes of headache with nausea and vomiting. It affects approximately 15% of the general population, yet the underlying pathophysiological mechanisms are not fully understood. Optical coherence tomography (OCT) is a safe and reproducible diagnostic technique that utilizes infrared wavelengths and has a sensitivity of 8–10 μm. It can be used to measure thinning of the retinal nerve fiber layer (RNFL) in some neurological disorders. Although ophthalmologists are often the first specialists to examine patients with migraine, few studies have addressed the involvement of the optic nerve ...

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    15. Optical Coherence Tomography in Patients With Chronic Migraine: Literature Review and Update

      Optical Coherence Tomography in Patients With Chronic Migraine: Literature Review and Update

      Migraine is a chronic disease characterized by unilateral, pulsating, and often moderate-to-severe recurrent episodes of headache with nausea and vomiting. It affects approximately 15% of the general population, yet the underlying pathophysiological mechanisms are not fully understood. Optical coherence tomography (OCT) is a safe and reproducible diagnostic technique that utilizes infrared wavelengths and has a sensitivity of 8-10 micrometers. It can be used to measure thinning of the retinal nerve fiber layer (RNFL) in some neurological disorders. Although ophthalmologists are often the first specialists to examine patients with migraine, few studies have addressed the involvement of the optic nerve and ...

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    16. Retinal thickness measured with optical coherence tomography and risk of disability worsening in multiple sclerosis: a cohort study

      Retinal thickness measured with optical coherence tomography and risk of disability worsening in multiple sclerosis: a cohort study

      Background Most patients with multiple sclerosis without previous optic neuritis have thinner retinal layers than healthy controls. We assessed the role of peripapillary retinal nerve fibre layer (pRNFL) thickness and macular volume in eyes with no history of optic neuritis as a biomarker of disability worsening in a cohort of patients with multiple sclerosis who had at least one eye without optic neuritis available. Methods In this multicentre, cohort study, we collected data about patients (age ≥16 years old) with clinically isolated syndrome, relapsing-remitting multiple sclerosis, and progressive multiple sclerosis. Patients were recruited from centres in Spain, Italy, France, Germany ...

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    17. No evidence of disease activity is associated with reduced rate of axonal retinal atrophy in MS

      No evidence of disease activity is associated with reduced rate of axonal retinal atrophy in MS

      Objective: To explore, in a longitudinal study, the usefulness of optical coherence tomography (OCT) in monitoring people with multiple sclerosis (MS) by testing the association between retinal nerve fiber layer (RNFL) thinning and clinical and brain MRI criteria of no evidence of disease activity (NEDA). Methods: OCT, visual evoked potentials (VEPs), and disability, using the Expanded Disability Status Scale (EDSS), were tested at baseline and after 2 years in 72 patients, 63 with routine yearly brain MRI. Results: Longitudinal mean binocular RNFL thinning, in absence of optic neuritis during follow-up, was correlated with EDSS worsening, also controlling for baseline EDSS ...

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    18. Beyond backscattering: Optical neuroimaging by BRAD

      Beyond backscattering: Optical neuroimaging by BRAD

      Optical coherence tomography (OCT) is a powerful technology for rapid volumetric imaging in biomedicine. The bright field imaging approach of conventional OCT systems is based on the detection of directly backscattered light, thereby waiving the wealth of information contained in the angular scattering distribution. Here we demonstrate that the unique features of few-mode fibers (FMF) enable simultaneous bright and dark field (BRAD) imaging for OCT. As backscattered light is picked up by the different modes of a FMF depending upon the angular scattering pattern, we obtain access to the directional scattering signatures of different tissues by decoupling illumination and detection ...

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    19. Heart-rate sensitive optical coherence angiography for measuring vascular changes due to posttraumatic brain injury in mice

      Heart-rate sensitive optical coherence angiography for measuring vascular changes due to posttraumatic brain injury in mice

      Traumatic brain injury (TBI) results in direct vascular disruption, triggering edema, and reduction in cerebral blood flow. Therefore, understanding the pathophysiology of brain microcirculation following TBI is important for the development of effective therapies. Optical coherence angiography (OCA) is a promising tool for evaluating TBI in rodent models. We develop an approach to OCA that uses the heart-rate frequency to discriminate between static tissue and vasculature. This method operates on intensity data and is therefore not phase sensitive. Furthermore, it does not require spatial overlap of voxels and thus can be applied to pre-existing datasets for which oversampling may not ...

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    20. Optical coherence tomography findings in Parkinson's disease

      Optical coherence tomography findings in Parkinson's disease

      The aim of this study is to compare optical coherence tomography (OCT) findings of retinal thickness (RT) and retinal nerve fiber layer thickness (RNFLT) of idiopathic Parkinson's disease (IPD) patients to those of healthy subjects, and to investigate whether there is any relationship between the severity of the disease and the RNFLT values. This prospective study was included 25 IPD patients and 29 healthy controls. In the IPD group, the Hoehn and Yahr (H&Y), Unified Parkinson's Disease Rating Scale (UPDRS), and Mini-Mental State Exam (MMSE) were performed. Intraocular pressure (IOP), visual acuity (VA), spherical equivalent, axial length ...

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    21. Image-guided recording system for spatial and temporal mapping of neuronal activities in brain slice

      Image-guided recording system for spatial and temporal mapping of neuronal activities in brain slice

      In this study, we introduce the novel image-guided recording system (IGRS) for efficient interpretation of neuronal activities in the brain slice. IGRS is designed to combine microelectrode array (MEA) and optical coherence tomography at the customized upright microscope. It allows to record multi-site neuronal signals and image the volumetric brain anatomy in a single body configuration. For convenient interconnection between a brain image and neuronal signals, we developed the automatic mapping protocol which enables for projecting acquired neuronal signals on a brain image. In order to evaluate the performance of IGRS, hippocampal signals of the brain slice were monitored, and ...

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    22. Visible Light Optical Coherence Microscopy of the Brain with Isotropic Femtoliter Resolution In Vivo

      Visible Light Optical Coherence Microscopy of the Brain with Isotropic Femtoliter Resolution In Vivo

      Most flying-spot Optical Coherence Tomography (OCT) and Optical Coherence Microscopy (OCM) systems use a symmetric confocal geometry, where the detection path retraces the illumination path starting from and ending with the spatial mode of a single mode optical fiber. Here, we describe a visible light OCM instrument that breaks this symmetry to improve transverse resolution without sacrificing collection efficiency. This was achieved by overfilling a water immersion objective on the illumination path, while maintaining a conventional Gaussian mode detection path (1/e2 intensity diameter ~0.82 Airy disks), enabling ~1.1 μm full-width at half-maximum (FWHM) transverse resolution. At the ...

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    23. The temporal retinal nerve fiber layer thickness is the most important optical coherence tomography estimate in multiple sclerosis

      The temporal retinal nerve fiber layer thickness is the most important optical coherence tomography estimate in multiple sclerosis

      Background: Reduced peripapillary retinal nerve fiber layer (pRNFL) and combined ganglion cell and inner plexiform layer (GCIP) thicknesses as measured by optical coherence tomography (OCT) have been observed in MS patients. The purpose was to determine the most associative OCT measure to level of cognitive and physical disability in MS. Methods: Data was collected from 546 MS patients and 175 healthy controls (HCs). We compared the average peripapillary RNFL (pRNFL), temporal pRNFL (tRNFL), overall inner ganglion cell/inner plexiform layer (GCIP) and the overall ganglion cell complex (GCC) including macular RNFL and GCIP thicknesses measurements in differentiating MS subtypes from ...

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    24. Optical coherence tomography in diagnosis and monitoring multiple sclerosis

      Optical coherence tomography in diagnosis and monitoring multiple sclerosis

      This paper presents application of optical coherence tomography (OCT) for diagnosis and monitoring of multiple sclerosis (MS). The peripapillary retinal nerve fibre layer thinning and the reduced total macular volume analysis are shown. With the course of the MS, the severity of these abnormalities increases which reflects the progressive degeneration of retinal ganglion cells and nerve fibres. The OCT parameters are sensitive, non-invasive indicators useful in assessing the progression of inflammation and neurodegeneration in MS.

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