1. Articles in category: Neurology

    1-24 of 495 1 2 3 4 ... 19 20 21 »
    1. 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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    2. 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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    3. 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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    4. Dynamic imaging and quantitative analysis of cranial neural tube closure in the mouse embryo using optical coherence tomography

      Dynamic imaging and quantitative analysis of cranial neural tube closure in the mouse embryo using optical coherence tomography

      Neural tube closure is a critical feature of central nervous system morphogenesis during embryonic development. Failure of this process leads to neural tube defects, one of the most common forms of human congenital defects. Although molecular and genetic studies in model organisms have provided insights into the genes and proteins that are required for normal neural tube development, complications associated with live imaging of neural tube closure in mammals limit efficient morphological analyses. Here, we report the use of optical coherence tomography (OCT) for dynamic imaging and quantitative assessment of cranial neural tube closure in live mouse embryos in culture ...

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    5. Polarization-Maintaining Fiber-Based Optical Coherence Tomography on Functional Imaging in Dense Nerve (Student Thesis)

      Polarization-Maintaining Fiber-Based Optical Coherence Tomography on Functional Imaging in Dense Nerve (Student Thesis)

      The technology and applications of optical coherence tomography (OCT) have been developed rapidly for structural and functional investigations of biological tissues. The use of light yields outstanding resolution and simultaneous measurements from a range of targeted locations without physical contact with tissue. The objective of this thesis was to investigate the feasibility of utilizing polarization-maintaining-fiber (PMF) based OCT to image the microstructure and functional (neural activity) of pike olfactory nerve. A dual-wavelength polarization-sensitive spectral-domain OCT system has been designed and constructed in house for depth-resolved optical recordings. The olfactory nerves dissected from pike were used with or without voltage-sensitive dye ...

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    6. Structural and Functional Analyses in Nonarteritic Anterior Ischemic Optic Neuropathy: Optical Coherence Tomography Angiography Study

      Structural and Functional Analyses in Nonarteritic Anterior Ischemic Optic Neuropathy: Optical Coherence Tomography Angiography Study

      Background: Retinal and optic disc perfusion in nonarteritic anterior ischemic optic neuropathy (NAION) is incompletely understood. Our aim was to investigate the characteristics of the microvascular structures at the peripapillary area and optic disc, and their associations with retinal structure and function in patients with NAION. Methods: We conducted a prospective, observational case series study. Thirty-four eyes, consisting of 15 NAION eyes and 19 normal eyes, were included. Optical coherence tomography (OCT) angiography was used to measure the vessel densities in the peripapillary superficial retina and whole-depth mode inside the optic disc. Measurement of circumpapillary retinal nerve fiber layer (cpRNFL ...

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    7. Optical coherence tomography: A quantitative tool to measure neurodegeneration and facilitate testing of novel treatments for tissue protection in multiple sclerosis

      Optical coherence tomography: A quantitative tool to measure neurodegeneration and facilitate testing of novel treatments for tissue protection in multiple sclerosis

      Optical coherence tomography (OCT) is a relatively new imaging technology that has been introduced as a powerful biomarker in neurological disease, including multiple sclerosis. In this review, OCT as an imaging technique, its reproducibility and validation in multiple sclerosis, application to other neurodegenerative diseases and future technological directions are discussed.

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    8. High-speed swept source optical coherence Doppler tomography for deep brain microvascular imaging

      High-speed swept source optical coherence Doppler tomography for deep brain microvascular imaging

      Noninvasive microvascular imaging using optical coherence Doppler tomography (ODT) has shown great promise in brain studies; however, high-speed microcirculatory imaging in deep brain remains an open quest. A high-speed 1.3 μm swept-source ODT (SS-ODT) system is reported which was based on a 200 kHz vertical-cavity-surface-emitting laser. Phase errors induced by sweep-trigger desynchronization were effectively reduced by spectral phase encoding and instantaneous correlation among the A-scans. Phantom studies have revealed a significant reduction in phase noise, thus an enhancement of minimally detectable flow down to 268.2 μm/s. Further in vivo validation was performed, in which 3D cerebral-blood-flow (CBF ...

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    9. Using light to map the circuitry of the brain

      Using light to map the circuitry of the brain

      Lehigh University bio-engineers are first to explore the use of highly-sensitive, non-invasive optical coherence tomography (OCT) to examine neuron-to-neuron communication in live tissue. Scientific progress has provided a solid understanding of the anatomy of the brain. However, there is still no reliable way to examine neuron to neuron communication, as it happens--a key to understanding the correlation between brain structure and brain function. Chao Zhou , assistant professor of bioengineering at Lehigh University, likens our current brain-mapping ability to a Global Positioning System (GPS) that can help a user locate a city, but cannot offer a street-level view. With current imaging ...

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    10. Optical coherence tomography imaging of capillary reperfusion after ischemic stroke

      Optical coherence tomography imaging of capillary reperfusion after ischemic stroke

      Although progress has been made for recanalization therapies after ischemic stroke, post-treatment imaging studies show that tissue reperfusion cannot be attained despite satisfactory recanalization in a significant percentage of patients. Hence, investigation of microcirculatory changes in both surface and deep cortical levels after ischemia reperfusion is important for understanding the post-stroke blood flow dynamics. In this study, we applied optical coherence tomography (OCT) imaging of cerebral blood flow for the quantification of the microcirculatory changes. We obtained OCT microangiogram of the brain cortex in a mouse stroke model and analyzed the data to trace changes in the capillary perfusion level ...

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    11. Collar Sign in Incompletely Occluded Aneurysms after Pipeline Embolization: Evaluation with Angiography and Optical Coherence Tomography

      Collar Sign in Incompletely Occluded Aneurysms after Pipeline Embolization: Evaluation with Angiography and Optical Coherence Tomography

      BACKGROUND AND PURPOSE: Flow diversion with the Pipeline Embolization Device has emerged as an attractive treatment for cerebral aneurysms. Processes involved in aneurysm occlusion include changes in intra-aneurysmal hemodynamics and endothelialization of the device. Here, we call attention to a radiographic sign not previously reported that is detected in incompletely occluded aneurysms after treatment with the Pipeline Embolization Device at angiographic follow-up and referred to as the “collar sign.” MATERIALS AND METHODS: A retrospective review of all patients who underwent placement of a Pipeline Embolization Device for cerebral aneurysms between January 2014 and May 2016 was performed. All aneurysms found ...

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    12. Optical Coherence Tomography and Magnetic Resonance Imaging in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder

      Optical Coherence Tomography and Magnetic Resonance Imaging in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder

      Irreversible disability in multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) is largely attributed to neuronal and axonal degeneration, which, along with inflammation, is one of the major pathological hallmarks of these diseases. Optical coherence tomography (OCT) is a non-invasive imaging tool that has been used in MS, NMOSD, and other diseases to quantify damage to the retina, including the ganglion cells and their axons. The fact that these are the only unmyelinated axons within the central nervous system (CNS) renders the afferent visual pathway an ideal model for studying axonal and neuronal degeneration in neurodegenerative diseases. Structural magnetic ...

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    13. Cerebral capillary velocimetry based on temporal OCT speckle contrast

      Cerebral capillary velocimetry based on temporal OCT speckle contrast

      We propose a new optical coherence tomography (OCT) based method to measure red blood cell (RBC) velocities of single capillaries in the cortex of rodent brain. This OCT capillary velocimetry exploits quantitative laser speckle contrast analysis to estimate speckle decorrelation rate from the measured temporal OCT speckle signals, which is related to microcirculatory flow velocity. We hypothesize that OCT signal due to sub-surface capillary flow can be treated as the speckle signal in the single scattering regime and thus its time scale of speckle fluctuations can be subjected to single scattering laser speckle contrast analysis to derive characteristic decorrelation time ...

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    14. Optical coherence tomography in an optic tract lesion, Retinal nerve fiber layer changes

      Optical coherence tomography in an optic tract lesion, Retinal nerve fiber layer changes

      A 49-year-old woman, status post temporal lobe resection, reported a hemianopia. Examination revealed a right afferent pupillary defect, horizontal bow-tie atrophy OD (temporal and nasal), and temporal atrophy OS. Optical coherence tomography showed a bow-tie pattern OD and predominant superior and inferior nerve fiber layer loss OS (figure 1; figure e-1 at Neurology.org ). The pattern OD is due to the combination of papillomacular bundle and nasal RNFL loss. The pattern OS is due to nerve fiber layer loss temporal to the fovea and, coupled with papillomacular bundle loss, produces temporal pallor. 1 MRI confirmed left optic tract atrophy (figure ...

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    15. Multimodal Optical Coherence Tomography in Visualization of Brain Tissue Structure at Glioblastoma (Experimental Study)

      Multimodal Optical Coherence Tomography in Visualization of Brain Tissue Structure at Glioblastoma (Experimental Study)

      The aim of the investigation was to evaluate the performance of multimodal OCT (MM OCT) for differential diagnostics of normal and diseased brain tissue using an experimental model of glioblastoma. Materials and Methods. The spectral domain MM OCT device developed at the Institute of Applied Physics of the Russian Academy of Sciences (Nizhny Novgorod, Russia) was used for the study. It provides two modes of investigation: cross-polarization OCT (CP OCT) and microangiographic OCT (MA OCT). The instrument features the following characteristics: rate of information gathering — 20,000 A-scans per second; wavelength — 1.3 µm; shot size — ~4 × 2 mm; lateral ...

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    16. Optical Coherence Tomography as a Biomarker for Diagnosis, Progression, and Prognosis of Neurodegenerative Diseases

      Optical Coherence Tomography as a Biomarker for Diagnosis, Progression, and Prognosis of Neurodegenerative Diseases

      Neurodegenerative diseases present a current challenge for accurate diagnosis and for providing precise prognostic information. Developing imaging biomarkers for multiple sclerosis (MS), Parkinson disease (PD), and Alzheimer’s disease (AD) will improve the clinical management of these patients and may be useful for monitoring treatment effectiveness. Recent research using optical coherence tomography (OCT) has demonstrated that parameters provided by this technology may be used as potential biomarkers for MS, PD, and AD. Retinal thinning has been observed in these patients and new segmentation software for the analysis of the different retinal layers may provide accurate information on disease progression and ...

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    17. Optical Coherence Tomography Angiography in Diabetes

      Optical Coherence Tomography Angiography in Diabetes

      Diabetic retinopathy is a progressive microvascular disease that leads to increased vessel permeability, retinal ischemia, and retinal neovascularization. Optical coherence tomography angiography (OCTA) is a novel angiography technique that has the capability to advance our understanding of diabetic eye disease by providing high-resolution images of retinal and choroidal microvasculature blood flow and structure. Using OCTA, the vascular changes of diabetic retinopathy including microaneurysms, retinal non-perfusion, intraretinal microvascular abnormalities, and neovascularization can be clearly visualized. OCTA offers several advantages over fluorescein angiography (FA) in that it is faster, safer, and non-invasive, allows better visualization of retinal vessels in both the superficial ...

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      Mentions: Richard B. Rosen
    18. Extended-focus optical coherence microscopy for high-resolution imaging of the murine brain

      Extended-focus optical coherence microscopy for high-resolution imaging of the murine brain

      We propose a new method and optical instrumentation for mouse brain imaging based on extended-focus optical coherence microscopy. This in vivo imaging technique allows the evaluation of the cytoarchitecture at cellular level and the circulation system dynamics in three dimensions. This minimally invasive and non-contact approach is performed without the application of contrasting agents. The optical design achieved a resolution of 2.2 μm over a distance of 800 μm, which was sufficient to obtain a detailed three-dimensional image of a wild-type mouse’s brain down to the layer III of the cortex. Intrinsically contrasted microvessels and structures similar to ...

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    19. Optical Coherence Tomography for Brain Imaging and Developmental Biology

      Optical Coherence Tomography for Brain Imaging and Developmental Biology

      Optical coherence tomography (OCT) is a promising research tool for brain imaging and developmental biology. Serving as a three-dimensional optical biopsy technique, OCT provides volumetric reconstruction of brain tissues and embryonic structures with micrometer resolution and video rate imaging speed. Functional OCT enables label-free monitoring of hemodynamic and metabolic changes in the brain in vitro and in vivo in animal models. Due to its noninvasiveness nature, OCT enables longitudinal imaging of developing specimens in vivo without potential damage from surgical operation, tissue fixation and processing, and staining with exogenous contrast agents. In this paper, various OCT applications in brain imaging ...

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    20. Periodic assessment with optical coherence tomography in children treated with multimodal therapies for brain tumors

      Periodic assessment with optical coherence tomography in children treated with multimodal therapies for brain tumors

      We performed a retrospective analysis on periodic ophthalmologic assessments with Optical Coherence Tomography (OCT), Best Corrected Visual Acuity (BCVA) and clinical optic examination (COE) in children treated for brain tumors. We identified 40 evaluable patients treated from 2003 to 2014 at our institution. Therapies was established on histology and staging. Surgery and radiotherapy were performed in 21 and 23 patients, respectively. All patients underwent to chemotherapy. Median follow-up time was 689 days. Regarding OCT, mean Retinal Nerve Fiber Layer (RNFL) thickness was measured by SD-OCT using the ONH and the nerve fiber 3D disc protocol. We calculated an average value ...

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    21. Optical Coherence Tomographic Angiography in Acute Macular Neuroretinopathy

      Optical Coherence Tomographic Angiography in Acute Macular Neuroretinopathy

      Importance Acute macular neuroretinopathy (AMN) is a rare, yet increasingly recognized, entity identified predominantly in young healthy females with acute onset of paracentral scotomas. The exact pathophysiology is unknown but an underlying vascular process is suspected. This study used optical coherence tomographic angiography (OCTA) to assess for any evidence of vascular flow abnormality in the retina or choroid in this elusive disease. Observations Three eyes from 2 young female patients with classic features of AMN are presented. Multimodal imaging testing, including near-infrared reflectance, spectral-domain OCT, and OCTA (Carl Zeiss Meditec), were performed. Near-infrared reflectance identified typical hyporeflective tear-drop parafoveal lesions ...

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    1-24 of 495 1 2 3 4 ... 19 20 21 »
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