1. Articles in category: Neurology

    1-24 of 357 1 2 3 4 ... 13 14 15 »
    1. Optical Coherence Tomography Opens a New Era in the Afferent Visual System Evaluation

      Optical Coherence Tomography Opens a New Era in the Afferent Visual System Evaluation

      For decades, thinning of the retinal nerve fiber layer in optic neuropathy could only be observed ophthalmoscopically or using red-free fundus photography. These days are over. Subsequently, different techniques to image the optic nerve and the retina have been developed. Optical coherence tomography (OCT) has gained the most attention and has opened a new area of revolutionary diagnostic possibilities. OCT is a noncontact diagnostic imaging technique that provides detailed, cross-sectional images of the retina and the optic disc in vivo. It was first used in 1991 to visualize the eye.[ 1 ] Image capture is noninvasive, painless, and fast. The technology ...

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    2. Applications of Optical Coherence Tomography in Pediatric Clinical Neuroscience

      Applications of Optical Coherence Tomography in Pediatric Clinical Neuroscience

      For nearly two centuries, the ophthalmoscope has permitted examination of the retina and optic nerve—the only axons directly visualized by the physician. The retinal ganglion cells project their axons, which travel along the innermost retina to form the optic nerve, marking the beginning of the anterior visual pathway. Both the structure and function of the visual pathway are essential components of the neurologic examination as it can be involved in numerous acquired, congenital and genetic central nervous system conditions. The development of optical coherence tomography now permits the pediatric neuroscientist to visualize and quantify the optic nerve and retinal ...

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    3. Measuring the optical characteristics of medulloblastoma with optical coherence tomography

      Measuring the optical characteristics of medulloblastoma with optical coherence tomography

      Medulloblastoma is the most common malignant pediatric brain tumor. Standard treatment consists of surgical resection, followed by radiation and high-dose chemotherapy. Despite these efforts, recurrence is common, leading to reduced patient survival. Even with successful treatment, there are often severe long-term neurologic impacts on the developing nervous system. We present two quantitative techniques that use a high-resolution optical imaging modality: optical coherence tomography (OCT) to measure refractive index, and the optical attenuation coefficient. To the best of our knowledge, this study is the first to demonstrate OCT analysis of medulloblastoma. Refractive index and optical attenuation coefficient were able to differentiate ...

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    4. Assessment of ultra-high resolution optical coherence tomography for monitoring tissue effects caused by laser photocoagulation of ex-vivo porcine retina

      Assessment of ultra-high resolution optical coherence tomography for monitoring tissue effects caused by laser photocoagulation of ex-vivo porcine retina

      Retinal laser photocoagulation is an established and successful treatment for a variety of retinal diseases. While being a valuable treatment modality, laser photocoagulation shows the drawback of employing high energy lasers which are capable of physically destroying the neural retina. For reliable therapy, it is therefore crucial to closely monitor the therapy effects caused in the retinal tissue. A depth resolved representation of optical tissue properties as provided by optical coherence tomography may provide valuable information about the treatment effects in the retinal layers if recorded simultaneously to laser coagulation. Therefore, in this work, the use of ultra-high resolution optical ...

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    5. Investigating the correlation between white matter and microvasculature changes in aging using large scale optical coherence tomography and confocal fluorescence imaging combined with tissue sectioning

      Investigating the correlation between white matter and microvasculature changes in aging using large scale optical coherence tomography and confocal fluorescence imaging combined with tissue sectioning

      Here, we present a serial OCT/confocal scanner for histological study of the mouse brain. Three axis linear stages combined with a sectioning vibratome allows to cut thru the entire biological tissue and to image every section at a microscopic resolution. After acquisition, each OCT volume and confocal image is re-stitched with adjacent acquisitions to obtain a reconstructed, digital volume of the imaged tissue. This imaging platform was used to investigate correlations between white matter and microvasculature changes in aging mice. Three age groups were used in this study (4, 12, 24 months). At sacrifice, mice were transcardially perfused with ...

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    6. Retinal Atrophy in Eyes With Resolved Papilledema Detected by Optical Coherence Tomography

      Retinal Atrophy in Eyes With Resolved Papilledema Detected by Optical Coherence Tomography

      Background: To apply automated spectral domain optical coherence tomography (SD-OCT) segmentation to eyes with resolving papilledema. Methods: Ninety-four patients with idiopathic intracranial hypertension seen at the Duke Eye Center neuro-ophthalmology clinic between November 2010 and October 2011 were reviewed. Excluded were eyes with papilledema with Frisen grade >2, other optic neuropathies or retinopathies, and those that did not have SD-OCT imaging. The remaining 43 patients were split into 2 groups: non-atrophic papilledema and atrophic papilledema. Automated SD-OCT segmentation was performed on patients with non-atrophic papilledema and age-matched controls for each of the 9 regions of the Early Treatment Diabetic Retinopathy ...

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    7. Retinal Ganglion Cell Layer Analysis by Optical Coherence Tomography in Toxic and Nutritional Optic Neuropathy

      Retinal Ganglion Cell Layer Analysis by Optical Coherence Tomography in Toxic and Nutritional Optic Neuropathy

      Objective: To analyze the retinal ganglion cell layer (RGL) by optical coherence tomography (OCT) in toxic and nutritional optic neuropathy and to correlate its thickness and volume with functional damage. Methods: We conducted an observational cross-sectional study in healthy subjects and in patients with toxic optic neuropathy observed in the Neuro-Ophthalmology Department of Central Lisbon Hospital Center. Complete ophthalmologic examination, OCT (Heidelberg Spectralis), and automated static perimetry were performed. Thickness and macular volume of RGL layer and inner plexiform layer were measured after manual segmentation. Results: The study included 16 eyes of 12 healthy subjects and 16 eyes of 8 ...

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    8. Optical Coherence Tomography versus Visual Evoked Potentials in detecting subclinical visual impairment in multiple sclerosis

      Optical Coherence Tomography versus Visual Evoked Potentials in detecting subclinical visual impairment in multiple sclerosis

      Rationale . Visual impairment is one of the most common clinical manifestations of multiple sclerosis (MS). Some multiple sclerosis patients complain of poor vision although the Snellen visual acuity is 20/20. This study reveals that sensitive measurements like visual evoked potential (VEP) and optical coherence tomography (OCT) can evidence subclinical disturbances of visual pathway. These methods examine the relation between the visual function (VEP) and retinal nerve fiber layer (RNFL) thickness, as a structural biomarker for axonal loss in patients with multiple sclerosis (MS). The findings in this study indicate the utility of combining structural and functional testing in clinical ...

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    9. In Vivo Characterization of Carotid Neointimal Hyperplasia by use of Optical Coherence Tomography: Before and After Cutting Balloon Angioplasty

      In Vivo Characterization of Carotid Neointimal Hyperplasia by use of Optical Coherence Tomography: Before and After Cutting Balloon Angioplasty

      Optical coherence tomography (OCT) is a modern intravascular imaging modality that has the capability to provide detailed, in vivo characterization of the arterial wall and atherosclerotic plaque. The current understanding of the appearance of atherosclerotic plaque via OCT is largely based on coronary arterial studies where OCT information has been employed to guide therapeutic management and permits the immediate evaluation of percutaneous intervention. The clinical success of OCT in the coronary arteries has laid the foundation for investigation of the carotid artery and thus, stroke risk assessment. We report the novel use of OCT for tissue characterization of severe stenosis ...

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    10. Optical coherence tomography predicts visual outcome for pituitary tumors

      Optical coherence tomography predicts visual outcome for pituitary tumors

      We evaluate if the relationship between optical coherence tomography (OCT) of the retinal nerve fibre layer (RNFL) continued over long-term visual recovery in 107 patients undergoing pituitary decompression. Recently, it has been recognized that OCT of RNFL has prognostic value in predicting visual outcomes after surgery for chiasmal compression caused by pituitary tumours. Patients were followed up at three time points: pre-operative (visit 1), 6 –10 weeks post-operative (visit 2) and 9–15 months follow-up (visit 3). We found that patients with thin pre-operative RNFL had more severe visual field defects (mean deviation [MD] -9.22 versus -3.96 decibels ...

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    11. Optical coherence tomography visualizes neurons in human entorhinal cortex

      Optical coherence tomography visualizes neurons in human entorhinal cortex

      The cytoarchitecture of the human brain is of great interest in diverse fields: neuroanatomy, neurology, neuroscience, and neuropathology. Traditional histology is a method that has been historically used to assess cell and fiber content in the ex vivo human brain. However, this technique suffers from significant distortions. We used a previously demonstrated optical coherence microscopy technique to image individual neurons in several square millimeters of en-face tissue blocks from layer II of the human entorhinal cortex, over 50     μ m in depth. The same slices were then sectioned and stained for Nissl substance. We registered the optical coherence tomography (OCT) images ...

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    12. Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography

      Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography

      Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber ...

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    13. OCT measurements of optic nerve head changes in idiopathic intracranial hypertension

      OCT measurements of optic nerve head changes in idiopathic intracranial hypertension

      Objective Severity of papilledema and vision loss constitute a basis for therapeutic intervention in idiopathic intracranial hypertension (IIH), but both are often subjective and insensitive in guiding clinical management. The aim of this study was to identify reliable and sensitive measurements of optic nerve head (ONH) and macula, to provide objective guidance for prognostic evaluation and treatment in IIH. We analyzed potential of spectral domain optical coherence tomography (SD-OCT), to measure neuro-retinal rim thickness and area, optic cup-to-disc ratio (C/D) and cup volume of ONH which have not previously been reported in IIH. In parallel, thickness of peripapillary retinal ...

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    14. Correlation between SD-OCT, immunocytochemistry and functional findings in an animal model of retinal degeneration

      Correlation between SD-OCT, immunocytochemistry and functional findings in an animal model of retinal degeneration

      Purpose: The P23H rhodopsin mutation is an autosomal dominant cause of retinitis pigmentosa (RP). The degeneration can be tracked using different anatomical and functional methods. In our case, we evaluated the anatomical changes using Spectral-Domain Optical Coherence Tomography (SD-OCT) and correlated the findings with retinal thickness values determined by immunocytochemistry.Methods: Pigmented rats heterozygous for the P23H mutation, with ages between P18 and P180 were studied. Function was assessed by means of optomotor testing and ERGs. Retinal thicknesses measurements, autofluorescence and fluorescein angiography were performed using Spectralis OCT. Retinas were studied by means of immunohistochemistry. Results: Between P30 and P180 ...

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    15. Optical coherence tomography and visual evoked potentials combined use as monitoring tools in Multiple Sclerosis patients

      Optical coherence tomography and visual evoked potentials combined use as monitoring tools in Multiple Sclerosis patients

      In Multiple Sclerosis-MS, optical coherence tomography-OCT is used to measure retinal nerve fiber layer-RNFL thickness as a marker of axonal loss and visual evoked potentials-VEPs as an indicator of demyelination. However, no clear indications are available on their combined use in MS monitoring. 80 MS patients underwent neurological and neurophysiological evaluation with OCT and VEPs, with routine clinical and MRI monitoring for a mean period of 1 year. Additional OCT-VEPs follow-up was obtained in 50 patients. Comparing eyes with and without previous ON, VEP latency and RNFL thickness were respectively significantly higher (131.2 ms Vs 118.8 ms, p ...

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    16. Optical Coherence Tomography to Assess Neurodegeneration in Multiple Sclerosis (Book Chapter)

      Optical Coherence Tomography to Assess Neurodegeneration in Multiple Sclerosis (Book Chapter)

      Retinal spectral domain optical coherence tomography (OCT) has emerged as a clinical and research tool in multiple sclerosis (MS) and optic neuritis (ON). This chapter summarizes a short OCT protocol as included in international consensus guidelines. The protocol was written for hands-on style such that both clinicians and OCT technicians can make use of it. The protocol is suitable for imaging of the optic nerve head and macular regions as a baseline for follow-up investigations, individual layer segmentation, and diagnostic assessment.

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    17. Examining multiple sclerosis through the eyes of a child

      Examining multiple sclerosis through the eyes of a child

      etinal ganglion cells (RGCs) receive input from photoreceptive cells, have unmyelinated axons that constitute the retinal nerve fiber layer (RNFL), and gain myelin as they pass through the lamina cribrosa to form the optic nerve. RGC axons project to several structures within the CNS, including the lateral geniculate nucleus of the thalamus. The ganglion cell layer (GCL) constitutes a readily quantifiable layer of neuronal cell bodies. Whereas research methods of cortical neuronal quantification in multiple sclerosis (MS) continue to evolve, the advent of high-resolution optical coherence tomography (OCT) images, derived from software that segments discrete retinal layers, has enabled quantification ...

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    18. Association of Cognitive deficits with Optical Coherence Tomography changes in Multiple Sclerosis Patients

      Association of Cognitive deficits with Optical Coherence Tomography changes in Multiple Sclerosis Patients

      Background: Multiple Sclerosis (MS) is a neurodegenerative disorder affecting myelinated axons. Cognitive impairments have been observed in patients with MS. Although there are some methods to examine the progress of MS, a tool hasn’t been developed to fully correlate MS symptoms with cognitive deficits. Methods: Among patients referring to Kerman-Iran Shafa Hospital, 60 MS patients were chosen to be included in the study. Their demographic data was obtained and patients filled the Brief International Cognitive Assessment for MS (BICAMS) questionnaire and then underwent OCT. The Chi-square test was used to analyze the frequency of patients with normal and abnormal ...

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    19. Evaluation of Retinal Nerve Fiber Layer in Patients with Idiopathic Optic Perineuritis using Optical Coherence Tomography

      Evaluation of Retinal Nerve Fiber Layer in Patients with Idiopathic Optic Perineuritis using Optical Coherence Tomography

      The aim of this study was to assess the effect of idiopathic Optic perineuritis on the retinal nerve fiber layer, and determine the ability of optical coherence tomography to evaluate retinal nerve fiber loss after idiopathic Optic perineuritis. Four patients were assessed in this study. In all cases, average retinal nerve fiber layer was significantly thinner in the affected eye in comparison with the normal reference value and with the value for the contralateral normal eye at 12 months after the onset of optic perineuritis. Our study revealed that retinal nerve fiber layer loss occurs in idiopathic optic nerve sheath ...

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    20. Retinal Ganglion Cell Analysis Using High-Definition Optical Coherence Tomography in Patients with Mild Cognitive Impairment and Alzheimer's Disease

      Retinal Ganglion Cell Analysis Using High-Definition Optical Coherence Tomography in Patients with Mild Cognitive Impairment and Alzheimer's Disease

      Background: Alzheimer's disease (AD) is a neurodegenerative disorder with emerging evidence that it is associated with retinal ganglion cell loss; however, few data exist to establish this association. Objective: To determine whether macular ganglion cell -inner plexiform layer (GC-IPL) and retinal nerve fiber layer (RNFL), as quantitatively measured by non-invasive in vivo spectral-domain optical coherence tomography (SD-OCT), are altered in patients with AD and mild cognitive impairment (MCI). Methods: Patients with AD and MCI were recruited from dementia/memory clinics, and cognitively normal controls were selected from the Singapore Epidemiology of Eye Disease program. SD-OCT (CIRRUS, software version 6 ...

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    21. Optical coherence tomography and its use in optical neuritis and multiple sclerosis

      Optical coherence tomography and its use in optical neuritis and multiple sclerosis

      Optical coherence tomography is a relatively new non-invasive imaging technique used for obtaining the images and quantifying the layers of the retina. It also provides information about optic nerve head topography, peripapillary retinal nerve fiber layer thickness, and macular volume which correlates with axonal loss. Until now, this method was used mainly in ophthalmology; now it has emerged as relevant in neurology as well. RNFL thickness is of particular interest in optic neuropathies and in multiple sclerosis. In sclerosis multiplex, axonal loss occurs as early as the first stages and the quantification of the RNFL thickness by OCT provides an ...

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    22. Applications of visual evoked potentials and Fourier-domain optical coherence tomography in Parkinson's disease: a controlled study

      Applications of visual evoked potentials and Fourier-domain optical coherence tomography in Parkinson's disease: a controlled study

      Purpose: The goal of this cross-sectional observational study was to quantify the pattern-shift visual evoked potentials (VEP) and the thickness as well as the volume of retinal layers using optical coherence tomography (OCT) across a cohort of Parkinson's disease (PD) patients and age-matched controls. Methods: Forty-three PD patients and 38 controls were enrolled. All participants underwent a detailed neurological and ophthalmologic evaluation. Idiopathic PD cases were included. Cases with glaucoma or increased intra-ocular pressure were excluded. Patients were assessed by VEP and high-resolution Fourier-domain OCT, which quantified the inner and outer thicknesses of the retinal layers. VEP latencies and ...

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    23. Multi-contrast optical coherence tomography for brain imaging and mapping (Thesis)

      Multi-contrast optical coherence tomography for brain imaging and mapping (Thesis)

      Although our knowledge of neuronal function and regional activity has been tremendously enriched in the past decades, coordination of these neurons to form the complex behaviors has yet to be understood. The neuronal pathways (also named connectome) form the structural foundation of the dynamic circuits in the brain. The recent interests in connectome and brainwide database have imposed a pressing need for high-resolution imaging techniques that allows large coverage. This dissertation develops a novel multi-contrast optical coherence tomography (MC-OCT) technique for the application of brainwide imaging and architectural mapping in 3D at high spatiotemporal resolution, with an emphasis on the ...

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    24. Monitoring of Cerebral Hemodynamics Post Optogenetic Stimulation via Optical Coherence Tomography

      Monitoring of Cerebral Hemodynamics Post Optogenetic Stimulation via Optical Coherence Tomography

      In this article Spectral Domain Optical Coherence Tomography is used to measure the hemodynamic response induced by optogenetic stimulation in the somatosensory cortex of transgenic mice. By analyzing the 3D angiograms and Doppler measurements produced by coherence tomography, we observed significant increase in blood flow as a result of increased vessel diameter and blood velocity following optical stimulation of cortical neurons. Such distinct responses were not observed in control experiments where the brain of wildtype mice were exposed to the same light pulses.

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    1-24 of 357 1 2 3 4 ... 13 14 15 »
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