1. Articles in category: Neurology

    1-24 of 516 1 2 3 4 ... 20 21 22 »
    1. Optical Coherence Angiographic Demonstration of Retinal Changes From Chronic Optic Neuropathies

      Optical Coherence Angiographic Demonstration of Retinal Changes From Chronic Optic Neuropathies

      Glaucoma causes a decrease in peripapillary perfused capillary density on optical coherence tomography (OCT) angiography. However, other chronic optic neuropathies have not been explored with OCT angiography to see if these changes were specific to glaucoma. The authors evaluated OCT angiography in 10 patients who suffered various kinds of chronic optic neuropathies, including optic neuritis and ischaemic optic neuropathy, and found that all optic neuropathies showed a decrease in peripapillary vessel density on OCT angiography, regardless of the aetiology of the optic neuropathy. The peripapillary vessel loss on OCT angiography correlated well with the areas of retinal nerve fibre layer ...

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    2. Optical Coherence Tomography Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy

      Optical Coherence Tomography Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy

      Background: Optical coherence tomography angiography (OCTA) has demonstrated good utility in qualitative analysis of retinal and choroidal vasculature and therefore may be relevant in the diagnostic and treatment efforts surrounding nonarteritic anterior ischemic optic neuropathy (NAION). Methods: Retrospective, cross-sectional study of 10 eyes of 9 patients with a previous or new diagnosis of NAION that received imaging with OCTA between November 2015 and February 2016. Two independent readers qualitatively analyzed the retinal peripapillary capillaries (RPC) and peripapillary choriocapillaris (PCC) for flow impairment. Findings were compared with automated visual field and structural optical coherence tomography (OCT) studies. Results: Flow impairment seen ...

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    3. Visual dysfunction and its correlation with retinal changes in patients with Alzheimer's disease

      Visual dysfunction and its correlation with retinal changes in patients with Alzheimer's disease

      Aim To evaluate visual dysfunction and its correlation with structural changes in the retina in patients with Alzheimer's disease (AD). Methods Patients with AD (n = 24) and controls (n = 24) underwent evaluation of visual acuity (VA), color vision (using the Farnsworth and L’Anthony desaturated (D) 15 color tests), and contrast sensitivity vision (CSV; using the Pelli-Robson chart and CSV-1000E test) to measure visual dysfunction. Structural measurements of the retinal nerve fiber layer (RNFL) and macular thickness were obtained using spectral domain-optical coherence tomography (SD-OCT). Results CSV at three of the four spatial frequencies was significantly worse in AD ...

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    4. Peripapillary retinal nerve fiber layer thickness and the evolution of cognitive performance in an elderly population

      Peripapillary retinal nerve fiber layer thickness and the evolution of cognitive performance in an elderly population

      Retinal Nerve Fiber Layer thickness (RNFL) is reduced in Alzheimer's patients. However, whether it is associated with early evolution of cognitive function is unknown. Within 427 participants from the 3C-Alienor longitudinal population-based cohort we explored the relationship between peripapillary RNFL thicknesses and the evolution of cognitive performance. RNFL was assessed at baseline by Spectral-Domain Optical Coherence Tomography; cognitive performances were assessed at baseline and at 2years, with the Mini Mental State Examination, the Isaacs' set test and the Free and Cued Selective Reminding Test (FCSRT). Multivariate linear mixed models were performed. The RNFL was not associated with initial cognitive ...

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    5. Anterior segment optical coherence tomography to look for Kayser-Fleischer rings

      Anterior segment optical coherence tomography to look for Kayser-Fleischer rings

      Ophthalmologists usually use slit lamp biomicroscopy to look for Kayser-Fleischer rings in Wilson’s disease; anterior segment optical coherence tomography is a new alternative to identify the characteristic hyper-reflective layer in the deep corneal periphery at the level of Descemet’s membrane. This method allows non-ophthalmologists to look for and to quantify Kayser-Fleischer rings.

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    6. Evaluation of Retinal Nerve Fiber Layer Thinning With Fourier-Domain Optical Coherence Tomography

      Evaluation of Retinal Nerve Fiber Layer Thinning With Fourier-Domain Optical Coherence Tomography

      Retinal nerve fiber layer (RNFL) defects are a defining feature of optic neuropathies and have been implicated in a few neurodegenerative disorders, including multiple sclerosis, 1 Alzheimer disease, 2 and Parkinson disease. 3 Ashina et al 4 conducted a prospective study observing 1406 children recruited from the Cophenhagen Child Cohort over 10 years. They showed that children of mothers with a history of smoking during pregnancy had a mean reduction in average circumpapillary RNFL thickness of 5.7 μm, adjusting for axial length, birth weight, and other covariates, compared with children without such history. Smoking during pregnancy has a detrimental ...

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    7. Mapping in-vivo optic nerve head strains caused by intraocular and intracranial pressures

      Mapping in-vivo optic nerve head strains caused by intraocular and intracranial pressures

      Although it is well documented that abnormal levels of either intraocular (IOP) or intracranial pressure (ICP) can lead to potentially blinding conditions, such as glaucoma and papilledema, little is known about how the pressures actually affect the eye. Even less is known about potential interplay between their effects, namely how the level of one pressure might alter the effects of the other. Our goal was to measure in-vivo the pressure-induced stretch and compression of the lamina cribrosa due to acute changes of IOP and ICP. The lamina cribrosa is a structure within the optic nerve head, in the back of ...

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    8. White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains

      White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains

      A whole rodent brain was imaged using an automated massive histology setup and an Optical Coherence Tomography (OCT) microscope. Thousands of OCT volumetric tiles were acquired, each covering a size of about 2.5x2.5x0.8 mm3 with a sampling resolution of 4.9x4.9x6.5 microns. This paper shows the techniques for reconstruction, attenuation compensation and segmentation of the sliced brains. The tile positions within the mosaic were evaluated using a displacement model of the motorized stage and pairwise coregistration. Volume blending was then performed by solving the 3D Laplace equation, and consecutive slices were assembled using the cross-correlation ...

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    9. Optical Coherence Tomography for the Noninvasive Detection of Elevated Intracranial Pressure A New Role for the Ophthalmologist?

      Optical Coherence Tomography for the Noninvasive Detection of Elevated Intracranial Pressure A New Role for the Ophthalmologist?

      Lumbar puncture is the usual confirmatory procedure for the diagnosis of idiopathic intracranial hypertension. However, the lumbar cerebrospinal fluid pressure does not always reflect the intracranial pressure (ICP), especially in children. 1 Therefore, direct ICP monitoring is the gold standard for ascertainment of ICP. However, this procedure is more invasive, requiring general anesthesia and hospital admission to monitor ICP over a period of days. It also carries low risk for central nervous system infection or injury. Consequently, newer techniques are being devised to noninvasively monitor ICP. 2

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    10. Rat brain imaging using full field optical coherence microscopy with short multimode fiber probe

      Rat brain imaging using full field optical coherence microscopy with short multimode fiber probe

      We demonstrated FF OCM(full field optical coherence microscopy) using an ultrathin forward-imaging SMMF (short multimode fiber) probe of 50 μm core diameter, 125 μm diameter, and 7.4 mm length, which is a typical graded-index multimode fiber for optical communications. The axial resolution was measured to be 2.20 μm, which is close to the calculated axial resolution of 2.06 μm. The lateral resolution was evaluated to be 4.38 μm using a test pattern. Assuming that the FWHM of the contrast is the DOF (depth of focus), the DOF of the signal is obtained at 36 μm ...

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    11. Spectroscopic optical coherence tomography for ex vivo brain tumor analysis

      Spectroscopic optical coherence tomography for ex vivo brain tumor analysis

      For neurosurgeries precise tumor resection is essential for the subsequent recovery of the patients since nearby healthy tissue that may be harmed has a huge impact on the life quality after the surgery. However, so far no satisfying methodology has been established to assist the surgeon during surgery to distinguish between healthy and tumor tissue. Optical Coherence Tomography (OCT) potentially enables non-contact in vivo image acquisition at penetration depths of 1-2 mm with a resolution of approximately 1-15 μm. To analyze the potential of OCT for distinction between brain tumors and healthy tissue, we used a commercially available Thorlabs Callisto ...

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    12. Retinal structure assessed by OCT as a biomarker of brain development in children born small for gestational age

      Retinal structure assessed by OCT as a biomarker of brain development in children born small for gestational age

      Purpose To identify differences in neuronal tissue from retinal and brain structures in children born small for gestational age (SGA) with no abnormality in neonatal brain ultrasonography and no previous neurological impairment, and to evaluate the relationship between retinal structure and brain changes in school-age children born SGA. Methods Two cohorts of children were recruited: 25 children born SGA and 25 children born with an appropriate birth weight according to gestational age. All the children underwent an ophthalmic examination, which included retinal imaging using spectral-domain optical coherence tomography, and a brain MRI. MRI images were automatically segmented and global and ...

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    13. Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

      Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

      Historically, regular drusen and geographic atrophy (GA) have been recognized as the hallmarks of nonneovascular age-related macular degeneration (AMD). Recent imaging developments have revealed another distinct nonneovascular AMD phenotype, reticular pseudodrusen (RPD). We develop an approach to semiautomatically quantify retinal surfaces associated with various AMD lesions (i.e., regular drusen, RPD, and GA) in spectral domain (SD) optical coherence tomography (OCT) images. More specifically, a graph-based algorithm was used to segment multiple retinal layers in SD-OCT volumes. Varying surface feasibility constraints based on the presegmentation were applied on the double-surface graph search to refine the surface segmentation. The thicknesses of ...

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    14. Using OCT with your diabetes patients

      Using OCT with your diabetes patients

      Patients with diabetes may present a variety of interesting findings best unveiled by use of spectral domain optical coherence tomography (SD-OCT). OCT is one of the best way to assess patients for the presence of diabetic macular edema (DME). It is extremely useful for monitoring responses to treatments such as anti-VEGF injections, grid or focal laser, intravitreal steroids, or any combination thereof in patients with DME involving or threatening the fovea (center-involved DME). However, detecting and monitoring increased retinal thickness associated with diabetes is not the only relevant anatomical feature best visualized and appreciated with OCT. Let’s consider a ...

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    15. Multimodal optical coherence tomography for in vivo imaging of brain tissue structure and microvascular network at glioblastoma

      Multimodal optical coherence tomography for in vivo imaging of brain tissue structure and microvascular network at glioblastoma

      In the case of infiltrative brain tumors the surgeon faces difficulties in determining their boundaries to achieve total resection. The aim of the investigation was to evaluate the performance of multimodal OCT (MM OCT) for differential diagnostics of normal brain tissue and glioma using an experimental model of glioblastoma. The spectral domain OCT device that was used for the study provides simultaneously two modes: cross-polarization and microangiographic OCT. The comparative analysis of the both OCT modalities images from tumorous and normal brain tissue areas concurrently with histologic correlation shows certain difference between when accordingly to morphological and microvascular tissue features.

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    16. Optical coherence tomography segmentation analysis in relapsing remitting versus progressive multiple sclerosis

      Optical coherence tomography segmentation analysis in relapsing remitting versus progressive multiple sclerosis

      Introduction Optical coherence tomography (OCT) with retinal segmentation analysis is a valuable tool in assessing axonal loss and neuro-degeneration in multiple sclerosis (MS) by in-vivo imaging, delineation and quantification of retinal layers. There is evidence of deep retinal involvement in MS beyond the inner retinal layers. The ultra-structural retinal changes in MS in different MS phenotypes can reflect differences in the pathophysiologic mechanisms. There is limited data on the pattern of deeper retinal layer involvement in progressive MS (PMS) versus relapsing remitting MS (RRMS). We have compared the OCT segmentation analysis in patients with relapsing-remitting MS and progressive MS. Methods ...

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    17. Optical coherence tomography angiography in eyes with good visual acuity recovery after treatment for optic neuritis

      Optical coherence tomography angiography in eyes with good visual acuity recovery after treatment for optic neuritis

      Objective To evaluate the retinal perfusion using optical coherence tomography (OCT) angiography in eyes with good visual acuity recovery after treatment for optic neuritis (ON). Methods Seven eyes of seven patients with good visual acuity recovery after treatment for monocular ON and seven eyes of each fellow eye used as controls were studied. Retinal perfusion around the disc and at the macula was evaluated using OCT angiography. The retinal nerve fiber layer thickness was measured around the disc. The ganglion cell layer complex thickness or the ganglion cell layer plus the inner plexiform layer thickness were measured at the macula ...

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    18. Northwestern University Receives a NIH Grant for A Clinically Applicable Model Of Retinal Oxygen Metabolism

      Northwestern University Receives a NIH Grant for A Clinically Applicable Model Of Retinal Oxygen Metabolism

      Northwestern University Receives at 2017 NIH Grant for $195,625 for A Clinically Applicable Model Of Retinal Oxygen Metabolism. The principal investigator is Robert Linsenmeier. The program began in 2017 and ends in 2019. Below is a summary of the proposed work. This proposal seeks to establish a correlation between the metabolism of the inner retina and the oxygen supply from the inner retinal vascular network measured by optical coherence tomography. This work will be done in rats, but will have immediate clinical application. Several important diseases cause damage to the inner retina, including diabetes, glaucoma, and vascular occlusion. Considerable ...

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    19. Polarization-sensitive optical coherence tomography of the human brain connectome

      Polarization-sensitive optical coherence tomography of the human brain connectome

      The human brain is composed of approximately 100 billion neurons that ‘communicate’ through an intricate network of axons and dendrites. 1 The difficulty of tracing these 3D neuronal pathways, however, has been a critical barrier for standard histology (the study of microscopic anatomy) over the past 100 years. Indeed, there is still no technology that can be used to acquire microscopic images in undistorted 3D space for mapping human brain connectivity. Currently available techniques for 3D brain mapping include histological staining and polarized light imaging. 2, 3 In these approaches, 2D image slices are obtained, but these must be physically ...

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    20. The role of optical coherence tomography in Alzheimer’s disease

      The role of optical coherence tomography in Alzheimer’s disease

      Background Alzheimer’s disease (AD) is the most common cause of dementia and its incidence is increasing worldwide along with population aging. Previous clinical and histologic studies suggest that the neurodegenerative process, which affects the brain, may also affect the retina of AD patients. Main body Optical coherence tomography (OCT) is a non-invasive technology that acquires cross-sectional images of retinal structures allowing neural fundus integrity assessment. Several previous studies demonstrated that both peripapillary retinal nerve fiber layer and macular thickness measurements assessed by OCT were able to detect neuronal loss in AD. Moreover, recent advances in OCT technology, have allowed ...

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    21. The University of Houston Receives NIH Grant for Optical Coherence Tomography to Study Effect of Poly-Drug Exposure on Fetal Brain Development

      The University of Houston Receives NIH Grant for Optical Coherence Tomography to Study Effect of Poly-Drug Exposure on Fetal Brain Development

      The University of Houston Receives a 2017 NIH Grant for $311,241 for Optical Coherence Tomography to Study Effect of Poly-Drug Exposure on Fetal Brain Development. The principal investigator is Kirll Larin. The program began in 2016 and ends in 2020. Below is a summary of the proposed work. The overall objective of this study is to develop an optical coherence tomography (OCT) based high- resolution mouse embryonic brain imaging and analysis approach, and to use this method in correlation with molecular analysis to understand the interplay between ethanol (EtOH) and nicotine (NIC) effects on embryonic brain development. Maternal exposures ...

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    22. Sensitivity of visual evoked potentials and spectral domain optical coherence tomography in early relapsing remitting multiple sclerosis

      Sensitivity of visual evoked potentials and spectral domain optical coherence tomography in early relapsing remitting multiple sclerosis

      Background Visual evoked potentials and spectral-domain optical coherence tomography are common ancillary studies that assess the visual pathways from a functional and structural aspect, respectively. Objective To compare prevalence of abnormalities of Visual evoked potentials (VEP) and spectral-domain optical coherence tomography (SDOCT) in patients with relapsing remitting multiple sclerosis (RRMS). Methods A cross-sectional study of 100 eyes with disease duration of less than 5 years since the diagnosis. Correlation between retinal nerve fiber layer and ganglion-cell/inner plexiform layer with pattern-reversal visual evoked potentials amplitude and latency and contrast sensitivity was performed. Results The prevalence of abnormalities in pattern-reversal visual ...

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    1-24 of 516 1 2 3 4 ... 20 21 22 »
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