1. Articles in category: Neurology

    1-24 of 486 1 2 3 4 ... 19 20 21 »
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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
    10. 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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    11. 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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    12. 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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    13. 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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    14. Visualizing and mapping the cerebellum with serial optical coherence scanner

      Visualizing and mapping the cerebellum with serial optical coherence scanner

      We present the visualization of the mouse cerebellum and adjacent brainstem using a serial optical coherence scanner, which integrates a vibratome slicer and polarization-sensitive optical coherence tomography for ex vivo imaging. The scanner provides intrinsic optical contrasts to distinguish the cerebellar cortical layers and white matter. Images from serial scans reveal the large-scale anatomy in detail and map the nerve fiber pathways in the cerebellum and brainstem. By incorporating a water-immersion microscope objective, we also present high-resolution tiled images that delineate fine structures in the cerebellum and brainstem.

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    15. Imaging Spinal Structures With Polarization-Sensitive Optical Coherence Tomography

      Imaging Spinal Structures With Polarization-Sensitive Optical Coherence Tomography

      Impact Statement: We investigate polarization-sensitive optical coherence tomography (PS-OCT) to obtain both intensity and polarization contrast images of in vivo and ex vivo spinal structures like subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, dura, and spinal cord in a piglet model. The PS-OCT can provide enhanced contrast characteristic structures compared to the intensity OCT; therefore it has the potential for guidance in spine interventional procedures. Abstract: We investigate polarization-sensitive optical coherence tomography (PS-OCT) to obtain both intensity and polarization contrast images of in vivo and ex vivo spinal structures like subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, dura ...

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    16. Optical Coherence Tomography (OCT) and Predicting Multiple Sclerosis (MS) Progression (Video)

      Optical Coherence Tomography (OCT) and Predicting Multiple Sclerosis (MS) Progression (Video)

      Retinal thickness is a significant independent predictor of worsening disability in multiple sclerosis (MS) and should be incorporated into clinical trials and treatment decisions, according to a large longitudinal cohort study presented at the American Academy of Neurology (AAN) Annual Meeting Optical coherence tomography (OCT), which is used to measure retinal thickness, can help clinicians predict multiple sclerosis (MS) progression two to five years later, according to an international longitudinal cohort study presented at the 2016 AAN Annual Meeting and published in Lancet Neurology. Overall, the researchers found that thinning in the peripapillary retinal nerve fiber of patients with either ...

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    17. Avoiding Clinical Misinterpretation and Artifacts of Optical Coherence Tomography Analysis of the Optic Nerve, Retinal Nerve Fiber Layer, and Ganglion Cell Layer

      Avoiding Clinical Misinterpretation and Artifacts of Optical Coherence Tomography Analysis of the Optic Nerve, Retinal Nerve Fiber Layer, and Ganglion Cell Layer

      Background: Optical coherence tomography (OCT) has become an important tool for diagnosing optic nerve disease. The structural details and reproducibility of OCT continues to improve with further advances in technology. However, artifacts and misinterpretation of OCT can lead to clinical misdiagnosis of diseases if they go unrecognized. Evidence Acquisition: A literature review using PubMed combined with clinical and research experience. Results: We describe the most common artifacts and errors in interpretation seen on OCT in both optic nerve and ganglion cell analyses. We provide examples of the artifacts, discuss the causes, and provide methods of detecting them. In addition, we ...

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    18. The association between retinal nerve fibre layer thickness and N-acetyl aspartate levels in multiple sclerosis brain normal-appearing white matter: a longitudinal study using magnetic resonance spectroscopy and optical coherence tomography

      The association between retinal nerve fibre layer thickness and N-acetyl aspartate levels in multiple sclerosis brain normal-appearing white matter: a longitudinal study using magnetic resonance spectroscopy and optical coherence tomography

      Background and purpose N -acetyl aspartate (NAA) assessed using proton magnetic resonance spectroscopy ( 1 H MRS) has a high pathological specificity for axonal density. Retinal nerve fibre layer thickness (RNFLT) measured by using optical coherence tomography is increasingly used as a surrogate marker of neurodegeneration in multiple sclerosis (MS). Our aim was to investigate the relation between RNFLT and NAA/creatine in brain normal-appearing white matter (NAWM), their dynamics over time and the association with clinical outcome measures in relapsing MS. T2 WM lesions served as control tissue. Methods Forty-three MS patients underwent standardized neurological examination including the Expanded Disability ...

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    19. Tail artifact removal in OCT angiography images of rodent cortex

      Tail artifact removal in OCT angiography images of rodent cortex

      Optical coherence tomography angiography (OCTA) is a surging non-invasive, label-free, in vivo volumetric imaging method, currently being translated to clinical ophthalmology and becoming popular in neuroscience. Despite its attractiveness, there is an inherent issue of using OCT angiograms for quantitative cerebrovascular studies: The dynamic scattering of moving erythrocytes within pial vasculature creates tail-like artifacts that shadow the capillary vessels in the deeper layers of cortex. This false flow effect is relatively benign for qualitative visualization purposes, but it might have a significant impact on quantitative interpretation of angiographic results. In this work, we propose a simple image processing method to ...

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    20. Evaluation of Retinal Vessel Morphology in Patients with Parkinson's Disease Using Optical ...

      Evaluation of Retinal Vessel Morphology in Patients with Parkinson's Disease Using Optical ...

      Purpose The retina has been found affected in Parkinson’s disease (PD). It is unclear if this is due to neurodegeneration of local dopamine-dependent retinal cells, a result of central nervous degeneration including the optic nerve or retinal small vessel disease. This study aimed to detect changes of the retinal vasculature in PD patients compared to controls. Methods We examined 49 PD patients and 49 age- and sex-matched healthy controls by spectral domain optical coherence tomography (SD-OCT) with a circular scan centred at the optic disc. Vessels within the retinal nerve fibre layer were identified by an automated algorithm and ...

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    21. News from the Alzheimer's Association International Conference: A View from the Retina May Help in Diagnosing Alzheimer's Disease

      News from the Alzheimer's Association International Conference: A View from the Retina May Help in Diagnosing Alzheimer's Disease

      People with the thinnest retinas scored poorly on a series of tests — memory, pair matching, numeric and verbal reasoning, and reaction time, according to a large study on retinal thinning and cognitive functioning. The team of scientists from the University College London Institute of Ophthalmology assessed the thickness of the retinal nerve fiber layer (RNFL) in 33,068 people — and conducted a series of cognitive tests, making it one of the largest studies of its type to date. The findings from the study were presented here in July in a session on biomarkers at the Alzheimer's Association International Conference ...

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    1-24 of 486 1 2 3 4 ... 19 20 21 »
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