1. Articles in category: Neurology

    1-24 of 218 1 2 3 4 5 6 7 8 9 »
    1. Imaging of non-tumorous and tumorous human brain tissues with full-field optical coherence tomography

      Imaging of non-tumorous and tumorous human brain tissues with full-field optical coherence tomography

      A prospective study was performed on neurosurgical samples from 18 patients to evaluate the use of full-field optical coherence tomography (FF-OCT) in brain tumor diagnosis. FF-OCT captures en face slices of tissue samples at 1 μm resolution in 3D to a penetration depth of around 200 μm. A 1 cm 2 specimen is scanned at a single depth and processed in about 5 min. This rapid imaging process is non-invasive and requires neither contrast agent injection nor tissue preparation, which makes it particularly well suited to medical imaging applications. Temporal chronic epileptic parenchyma and brain tumors such as meningiomas, low-grade ...

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    2. Correlation of Inner Retinal Thickness Evaluated by Spectral-Domain Optical Coherence Tomography and Contrast Sensitivity in Parkinson disease

      Correlation of Inner Retinal Thickness Evaluated by Spectral-Domain Optical Coherence Tomography and Contrast Sensitivity in Parkinson disease

      Background: To compare inner retinal layer (IRL) thickness measured by spectral-domain optical coherence tomography (SD-OCT) and contrast sensitivity (CS) in patients with Parkinson disease (PD) and in healthy control (HC) subjects. Methods: Consecutive patients with and without PD were prospectively analyzed using SD-OCT and Pelli-Robson CS testing. SD-OCT IRL (ganglion-cell complex) thickness, consisting of the nerve fiber layer, ganglion cell layer, and inner plexiform layer, was segmented using an RTVue Model-RT100 with an EMM5 scan parameter covering a 5.0 x 5.0 mm cube centered on the fovea. Thickness voxel measurements at 0.25-mm intervals at sequential radial distances ...

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    3. Photoacoustic and optical coherence tomography of epilepsy with high temporal and spatial resolution and dual optical contrasts

      Photoacoustic and optical coherence tomography of epilepsy with high temporal and spatial resolution and dual optical contrasts

      Epilepsy mapping with high spatial and temporal resolution has great significance for both fundamental research on epileptic neurons and the clinical management of epilepsy. In this communication, we demonstrate for the first time in vivo epilepsy mapping with high spatial and temporal resolution and dual optical contrasts in an animal model. Through the variations of a depthresolved optical coherence tomography signal with optical scattering contrast, we observed that epileptic neuron activities modulated the optical refractive index of epileptic neurons and their surrounding tissue. Simultaneously, through neurovasculature coupling mechanisms and optical absorption contrast, we used photoacoustic signals to document the hemodynamic ...

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    4. Johns Hopkins University Receives 2013 NIH Grant for Imaging Neurodegeneration in Multiple Sclerosis

      Johns Hopkins University Receives 2013 NIH Grant for Imaging Neurodegeneration in Multiple Sclerosis

      Johns Hopkins University Receives 2013 NIH Grant for $438,855 Imaging Neurodegeneration in Multiple Sclerosis. The principal investigator is Peter Calabresi. The program is part of a multiyear program that started in 2013 and ends in 2018. Below is a summary of the work. There is emerging evidence that gray matter (GM) degeneration is common in multiple sclerosis (MS), and more closely linked with disability than white matter (WM) injury. Indeed, WM volumes, as measured by high resolution MRI, wax and wane as a reflection of inflammation, whereas GM atrophy accelerates with time in MS. Whether GM degeneration purely results ...

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    5. A common-path optical coherence tomography based electrode for structural imaging of nerves and recording of action potentials

      A common-path optical coherence tomography based electrode for structural imaging of nerves and recording of action potentials

      Current technologies for monitoring neural activity either use different variety of electrodes (electrical recording) or require contrast agents introduced exogenously or through genetic modification (optical imaging). Here we demonstrate an optical method for non-contact and contrast agent free detection of nerve activity using phase-resolved optical coherence tomography (pr-OCT). A common-path variation of the pr-OCT is recently implemented and the developed system demonstrated the capability to detect rapid transient structural changes that accompany neural spike propagation. No averaging over multiple trials was required, indicating its capability of single-shot detection of individual impulses from functionally stimulated Limulus optic nerve. The strength of ...

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    6. Retinal Nerve Fiber Layer Thickness in Parkinson Disease

      Retinal Nerve Fiber Layer Thickness in Parkinson Disease

      Dopaminergic neuronal cells have been identified in the inner nuclear and inner plexiform layers of the human retina. The dopaminergic content of the retina is reduced in patients with idiopathic Parkinson disease (PD). These observations led us to study the retinal nerve fiber layer (RNFL) thickness in patients with PD without visual impairment compared to healthy controls using spectral-domain optical coherence tomography (SD-OCT). Eighty-two subjects, including 42 patients with PD, newly diagnosed and untreated (24 men, 18 women, age range: 47–66 years), and 40 healthy controls, were enrolled. Both eyes of patients with PD and controls were imaged with ...

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    7. Retinal Nerve Fiber Layer Thickness in Patients With Alzheimer Disease

      Retinal Nerve Fiber Layer Thickness in Patients With Alzheimer Disease

      Abstract: The aim of this study was to investigate retinal nerve fiber layer (RNFL) thickness in patients with Alzheimer disease (AD) without visual impairment using spectral domain optical coherence tomography (SD-OCT) and to compare the results with healthy controls. A total of 80 subjects, including 40 patients with early untreated AD (mean age, 69.3 ± 4.9 years) and 40 healthy controls (mean age, 68.9 ± 5.1 years) were enrolled. Both eyes of patients with AD and controls were imaged using SD-OCT. The average RNFL thickness was significantly less in the AD patients than in controls (65 ± 6.2 ...

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    8. Longitudinal follow-up of vision in a neuromyelitis optica cohort

      Longitudinal follow-up of vision in a neuromyelitis optica cohort

      Background: Neuromyelitis optica (NMO) is an inflammatory disease associated with optic neuritis and myelitis. Recently, several studies showed that optical coherence tomography (OCT) could be an interesting method for the evaluation of disease severity; however, to date there are no studies with a longitudinal follow-up of visual function in NMO. The aim of this study was to assess the ability of OCT to evaluate the progression of visual dysfunction in NMO. Patients and methods: A group of 30 NMO patients (thus, 60 eyes), comprised of 20 women and 10 men with a mean age of 43.7 +/− 12.3 years ...

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    9. Neuroimaging of the afferent visual system

      Neuroimaging of the afferent visual system

      Neuroimaging studies provide a useful tool for the clinician evaluating a patient with visual loss. In this review, we discuss the use of magnetic resonance imaging (MRI), computed tomography (CT), orbital ultrasound, and optical coherence tomography (OCT) for evaluating causes of visual loss affecting the afferent visual system. The imaging characteristics of diseases affecting the optic nerve, orbit, sellar and parasellar region, optic tracts, and retrogeniculate visual pathways will be discussed.

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    10. Living Brain Optical Imaging: Technology, Methods and Applications

      Living Brain Optical Imaging: Technology, Methods and Applications

      Within the last few decades, optical imaging methods have yielded revolutionary results when applied to all parts of the central nervous system. The purpose of this review is to analyze research possibilities and limitations of several novel imaging techniques and show some of the most interesting achievements obtained by these methods. Here we covered intrinsic optical imaging, voltage-sensitive dye, photoacoustic, optical coherence tomography, near-infrared spectroscopy and some other techniques. All of them are mainly applicable for experimental neuroscience but some of them also suitable for the clinical studies.

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    11. Coronal in vivo forward-imaging of rat brain morphology with an ultra-small optical coherence tomography fiber probe

      Coronal in vivo forward-imaging of rat brain morphology with an ultra-small optical coherence tomography fiber probe

      A well-established navigation method is one of the key conditions for successful brain surgery: it should be accurate, safe and online operable. Recent research shows that optical coherence tomography (OCT) is a potential solution for this application by providing a high resolution and small probe dimension. In this study a fiber-based spectral-domain OCT system utilizing a super-luminescent-diode with the center wavelength of 840 nm providing 14.5 μm axial resolution was used. A composite 125 μm diameter detecting probe with a gradient index (GRIN) fiber fused to a single mode fiber was employed. Signals were reconstructed into grayscale images by ...

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    12. Getting Beyond the Ganglion Cell Morphometric Adjustments for Retinal Optical Coherence Tomography in Multiple Sclerosis

      Getting Beyond the Ganglion Cell Morphometric Adjustments for Retinal Optical Coherence Tomography in Multiple Sclerosis

      The treatment of relapsing multiple sclerosis (MS) remains a rare beacon of success in the long campaign against neurological disease. The ready availability of a phase II clinical outcome (eg, gadolinium-enhancing lesion) that tracks a relevant phase III clinical outcome (eg, annualized relapse rate) is one of the major reasons for this success. Eight therapies have been approved by the US Food and Drug Administration in less than 20 years, and 3 more are under current consideration at the Food and Drug Administration following successful phase III clinical programs. However, before feeling triumphant, we must recognize that our current therapies ...

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      Mentions: FDA
    13. In Vivo Demonstration of Homonymous Hemimacular Loss of Retinal Ganglion Cells Due to a Thalamic Lesion Using Optical Coherence Tomography

      In Vivo Demonstration of Homonymous Hemimacular Loss of Retinal Ganglion Cells Due to a Thalamic Lesion Using Optical Coherence Tomography

      A previously healthy 40-year-old woman presented with subacute onset of a left homonymous hemianopia. Contrast-enhanced magnetic resonance imaging of the brain revealed a T2-hyperintense lesion in the right thalamus, with associated subtle gadolinium enhancement ( Figure 1 ), and a small periventricular lesion. Although her visual symptoms were improving, a new left-sided hemiparesis developed 3 weeks later. Additional magnetic resonance imaging of the brain showed extension of the original thalamic lesion into the right internal capsule, with persistent contrast enhancement. Her visual and motor symptoms gradually improved over 3 months.

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    14. Simple eye scan can reveal how quickly Multiple Sclerosis will progress

      Simple eye scan can reveal how quickly Multiple Sclerosis will progress

      A quick and easy eye test could offer an effective way of measuring how fast multiple sclerosis is progressing in someone with the disease. Researchers performed scans on 164 M.S patients that measured the thickness of the lining at the back of the eye. The team from John Hopkins University found patients with thinning of the retina had both earlier and more active forms of the disease.

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    15. Active MS is associated with accelerated retinal ganglion cell/inner plexiform layer thinning

      Active MS is associated with accelerated retinal ganglion cell/inner plexiform layer thinning

      Objective: To determine the effect of clinical and radiologic disease activity on the rate of thinning of the ganglion cell/inner plexiform (GCIP) layer and the retinal nerve fiber layer in patients with multiple sclerosis (MS) using optical coherence tomography (OCT). Methods: One hundred sixty-four patients with MS and 59 healthy controls underwent spectral-domain OCT scans every 6 months for a mean follow-up period of 21.1 months. Baseline and annual contrast-enhanced brain MRIs were performed. Patients who developed optic neuritis during follow-up were excluded from analysis. Results: Patients with the following features of disease activity during follow-up had faster ...

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    16. Retinal Neurodegeneration in Wilson’s Disease Revealed by Spectral Domain Optical Coherence Tomography

      Retinal Neurodegeneration in Wilson’s Disease Revealed by Spectral Domain Optical Coherence Tomography

      Background/Objective In addition to cirrhosis of the liver, Wilson’s disease leads to copper accumulation and widespread degeneration of the nervous system. Delayed visual evoked potentials (VEPs) suggest changes to the visual system and potential structural changes of the retina. Methods We used the latest generation of spectral domain optical coherence tomography to assess the retinal morphology of 42 patients with Wilson’s disease and 76 age- and sex-matched controls. We measured peripapillary retinal nerve fiber layer (RNFL) thickness and total macular thickness and manually segmented all retinal layers in foveal scans of 42 patients with Wilson’s disease ...

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    17. The Use of Fourth-generation Optical Coherence Tomography in Multiple Sclerosis: A Review

      The Use of Fourth-generation Optical Coherence Tomography in Multiple Sclerosis: A Review

      Optical coherence tomography (OCT) has been routinely used to obtain high spatial resolution images of the retina and choroid non-invasively. Within the past decade, a fourth-generation OCT device using Fourier domain (FD) analysis has been developed that provides higher velocity and higher axial resolution images with better reproducibility than the previous generation time domain (TD) OCT technology. This review addresses the use of fourth-generation, FD ocular OCT in patients with multiple sclerosis.

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    18. Retinal Neurodegeneration in Wilson’s Disease Revealed by Spectral Domain Optical Coherence Tomography

      Retinal Neurodegeneration in Wilson’s Disease Revealed by Spectral Domain Optical Coherence Tomography

      Background/Objective In addition to cirrhosis of the liver, Wilson’s disease leads to copper accumulation and widespread degeneration of the nervous system. Delayed visual evoked potentials (VEPs) suggest changes to the visual system and potential structural changes of the retina. Methods We used the latest generation of spectral domain optical coherence tomography to assess the retinal morphology of 42 patients with Wilson’s disease and 76 age- and sex-matched controls. We measured peripapillary retinal nerve fiber layer (RNFL) thickness and total macular thickness and manually segmented all retinal layers in foveal scans of 42 patients with Wilson’s disease ...

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    19. Optical Coherence Tomography for Brain Imaging

      Optical Coherence Tomography for Brain Imaging

      Recently, there has been growing interest in using OCT for brain imaging. A feasibility study of OCT for guiding deep brain probes has found that OCT can differentiate the white matter and gray matter because the white matter tends to have a higher peak reflectivity and steeper attenuation rate compared to gray matter. In vivo 3D visualization of the layered organization of a rat olfactory bulb with OCT has been demonstrated. OCT has been used for single myelin fiber imaging in living rodents without labeling. The refractive index in the rat somatosensory cortex has also been measured with OCT. In ...

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    20. A Simple Sign for Recognizing Off–Axis OCT Measurement Beam Placement in the Context of Multicentre Studies

      A Simple Sign for Recognizing Off–Axis OCT Measurement Beam Placement in the Context of Multicentre Studies

      Purpose Optical coherence tomography (OCT) allows quantification of the thickness of the retinal nerve fibre layer (RNFL) thickness, a potential biomarker for neurodegeneration. The estimated annual RNFL loss in multiple sclerosis amounts to 2 μ m using time domain OCT. The recognition of measurement artifacts exceeding this limit is relevant for the successful use of OCT as a secondary outcome measure in clinical trials. Methods Prospective study design. An exploratory pilot study (ring and volume scans) followed by a cohort study (1,980 OCT ring scans). The OCT measurement beam was placed off–axis to the left, right, top and bottom ...

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    21. California Doctor’s Medical-Imaging Research Will Help Physicians Better Detect Cancer, Brain Disease

      California Doctor’s Medical-Imaging Research Will Help Physicians Better Detect Cancer, Brain Disease

      The skyrocketing costs of health care are driving the need for more noninvasive, safe medical imaging as patients look to forego expensive hospital visits for less costly treatment at local health clinics. Dr. Akash Singh, a resident of Sacramento, Calif., said his recent contributions to the field of medical imaging will make it possible for any physician to detect cancer and brain diseases more quickly and efficiently in patients who may not know they have the deadly ailments. Research being performed by scientists like Singh is giving hope to those who suffer from Parkinson’s disease, Alzheimer’s disease and ...

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    22. Using The Eye as a "Window To The Brain"

      Using The Eye as a "Window To The Brain"

      -Quick, cheap retina scan can predict brain damage caused by multiple sclerosis An inexpensive, five-minute eye scan can accurately assess the amount of brain damage in people with the debilitating autoimmune disorder multiple sclerosis (MS), and offer clues about how quickly the disease is progressing, according to results of two Johns Hopkins studies. "The eye is the window into the brain and by measuring how healthy the eye is, we can determine how healthy the rest of the brain is," says Peter A. Calabresi, M.D., a professor of neurology at the Johns Hopkins University School of Medicine, and leader ...

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    1-24 of 218 1 2 3 4 5 6 7 8 9 »
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