1. Articles in category: Neurology

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    1. Choroidal Thickness in Multiple Sclerosis: An Optical Coherence Tomography Study

      Choroidal Thickness in Multiple Sclerosis: An Optical Coherence Tomography Study

      Background and Purpose To identify changes in the choroidal thickness (CT) in multiple sclerosis (MS) patients with and without optic neuritis (ON) using enhanced-depth-imaging optical coherence tomography (EDI-OCT). Methods This cross-sectional study included 96 eyes with MS and 28 eyes of healthy controls. All participants underwent an ophthalmologic examination and EDI-OCT scanning (Spectralis, Heidelberg Engineering, Germany) to assess the CT and the retinal nerve fiber layer (RNFL) thickness. MS patients were divided into two groups: 1) with and 2) without a history of ON. The CT was evaluated in the fovea and at six horizontal and six vertical points at ...

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      Mentions: UCSF
    2. Applications of Visible-Light Optical Coherence Tomography in the Eye and Brain -

      Applications of Visible-Light Optical Coherence Tomography in the Eye and Brain -

      Optical coherence tomography (OCT) is a non-invasive, label-free technology that can image biological tissues in vivo with micrometer-scale resolution. Since its development in 1991, OCT has been successfully commercialized and widely adopted in the clinic for the diagnosis and monitoring of retinal diseases. A typical commercial OCT system may have an axial resolution of 5-10 micrometers. By shortening the wavelength range of the light source, visible-light OCT (vis-OCT) enables an improved axial resolution of 1-micrometer, improved tissue scattering contrasts, and additional functional information. The bulk of this dissertation focuses on vis-OCT imaging of the Schlemm’s canal and limbal vascular ...

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    3. A novel algorithm for multiplicative speckle noise reduction in ex vivo human brain OCT images

      A novel algorithm for multiplicative speckle noise reduction in ex vivo human brain OCT images

      Optical coherence tomography (OCT) images of ex vivo human brain tissue are corrupted by multiplicative speckle noise that degrades the contrast to noise ratio (CNR) of microstructural compartments. This work proposes a novel algorithm to reduce noise corruption in OCT images that minimizes the penalized negative log likelihood of gamma distributed speckle noise. The proposed method is formulated as a majorize-minimize problem that reduces to solving an iterative regularized least squares optimization. We demonstrate the usefulness of the proposed method by removing speckle in simulated data, phantom data and real OCT images of human brain tissue. We compare the proposed ...

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    4. Volumetric characterization of microvasculature in ex vivo human brain samples by serial sectioning optical coherence tomography

      Volumetric characterization of microvasculature in ex vivo human brain samples by serial sectioning optical coherence tomography

      Objective: Serial sectioning optical coherence tomography (OCT) enables distortion-free volumetric reconstruction of several cubic centimeters of human brain samples. We aimed to identify anatomical features of the ex vivo human brain, such as intraparenchymal blood vessels and axonal fiber bundles, from the OCT data in 3D, using intrinsic optical contrast. Methods: We developed an automatic processing pipeline to enable characterization of the intraparenchymal microvascular network in human brain samples. Results: We demonstrated the automatic extraction of the vessels down to a 20 m in diameter using a filtering strategy followed by a graphing representation and characterization of the geometrical properties ...

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    5. No optical coherence tomography changes in premanifest Huntington's disease mutation carriers far from disease onset

      No optical coherence tomography changes in premanifest Huntington's disease mutation carriers far from disease onset

      Background: Spectral-domain optical coherence tomography (OCT) may detect retinal changes as a biomarker in neurodegenerative diseases like manifest Huntington's disease (HD). We investigate macular retinal layer thicknesses in a premanifest HD (pre-HD) cohort and healthy controls (HC). Methods: Pre-HD mutation carriers underwent standardized ratings and a preset macular OCT scan. Thickness values were determined for each sector of all macular retinal layers, the mean of all sectors and the mean of the inner ring (IR, 3 mm) after segmentation (Heyex segmentation batch). HC were retrospectively included from an existing database. The IR thickness of the ganglion cell layer (GCL ...

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    6. Fiber-laser platform for precision brain surgery

      Fiber-laser platform for precision brain surgery

      Minimally invasive neurological surgeries are increasingly being sought after for treatment in neurological pathologies and oncology. A critical limitation in these minimally invasive procedures is lack of specialized tools that allow for space-time controlled delivery of sufficient energy for coagulation and cutting of tissue. Advent of fiber-lasers provide high average power with improved beam quality (lower M 2 ), biocompatible silica fiber delivery, reduced cost of manufacturing, and radiant output stability over long operating periods. Despite these advancements, no fiber-laser based surgical tools are currently available for tissue resection in vivo . Here we demonstrate a first to our knowledge, fiber-laser platform ...

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    7. Registration of histological brain images onto optical coherence tomography images based on shape information

      Registration of histological brain images onto optical coherence tomography images based on shape information

      Identifying tumour infiltration zones during tumour resection in order to excise as much tumour tissue as possible without damaging healthy brain tissue is still a major challenge in neurosurgery. The detection of tumour infiltrated regions so far requires histological analysis of biopsies taken from at expected tumour boundaries. The gold standard for histological analysis is the staining of thin cut specimen and the evaluation by a neuropathologist. This work presents a way to transfer the histological evaluation of a neuropathologist onto optical coherence tomography (OCT) images. OCT is a method suitable for real time in vivo imaging during neurosurgery however ...

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    8. Early Retinal Microcirculation in Nonfunctioning Pituitary Adenomas Without Visual Field Defects Using Optical Coherence Tomography Angiography

      Early Retinal Microcirculation in Nonfunctioning Pituitary Adenomas Without Visual Field Defects Using Optical Coherence Tomography Angiography

      Background: For patients with nonfunctioning pituitary adenoma (NFPA) without manifesting visual acuity impairment or visual field defect (VFD), more sensitive and objective assessment methods will allow earlier detection before irreversible damage to the visual system. This study aimed to evaluate retinal vessel densities (VDs) alterations in these patients using optical coherence tomography angiography and to determine its diagnostic abilities. Methods: Between patients with NFPA without VFDs and age-matched, sex-matched healthy control individuals, comparisons of visual field metrics, retinal structural thickness, and microcirculation were conducted after adjusting for axial length (AL) and signal index of scans. Receiver operating characteristic (ROC) curves ...

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    9. Optical Coherence Tomography and Visual Evoked Potential Testing for Noninvasive Intracranial Pressure Monitoring in Craniosynostosis

      Optical Coherence Tomography and Visual Evoked Potential Testing for Noninvasive Intracranial Pressure Monitoring in Craniosynostosis

      Elevated intracranial pressure is sometimes observed in the setting of craniosynostosis. Common clinical symptoms include headaches, nausea, vomiting, developmental delays, and visual disturbances. 1 Some of these symptoms may be mild and unspecific in the pediatric population. In other cases, pediatric patients can present late for evaluation by the craniofacial surgeon with more concerning signs of intracranial hypertension. 2 Fundoscopic examination is commonly utilized for noninvasive evaluation of elevated intracranial pressure; however, this method has poor sensitivity in children. 3 Therefore, patients may require more sensitive and specific methods of intracranial pressure monitoring for appropriate timing and planning of operative ...

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    10. Juxtapapillary Choroidal Neovascular Membrane as a Complication of Optic Disc Drusen: Multimodal Imaging With Swept Source-Optical Coherence Tomography and Optical Coherence Tomography Angiography

      Juxtapapillary Choroidal Neovascular Membrane as a Complication of Optic Disc Drusen: Multimodal Imaging With Swept Source-Optical Coherence Tomography and Optical Coherence Tomography Angiography

      A 55-year-old Caucasian man presented to the neuro-ophthalmology department for follow-up evaluation due to long-standing bilateral optic nerve head drusen (ONHD). On examination, the BCVA was 20/20-2 in both eyes. Dilated fundus examination revealed extensive ONHD in both eyes, retinal hemorrhages, exudates inferonasal to the macula, and macular edema inferotemporal to the disc margin. Automated visual field testing revealed generalized depression in both eyes. Late phase leakage was observed on fluorescein angiography (FA). Optical coherence tomography angiography identified a small juxtapapillary choroidal neovascular membrane inferonasal to the macula in the right eye correlating with the area of retinal hemorrhage ...

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    11. Optical coherence tomography reveals heterogeneity of the brain tissue and vasculature in the ischemic region after photothrombotic stroke in mice

      Optical coherence tomography reveals heterogeneity of the brain tissue and vasculature in the ischemic region after photothrombotic stroke in mice

      We demonstrate in vivo imaging of the ischemic area in the mouse brain after photostroke using a custom prototype Gaussian‑beam optical coherence tomography (OCT) setup in which the near infrared imaging beam and the green photoinducing light pass through the same objective lens. The goal of our research was analysis of vascularity of the ischemic area during 2‑week progress of stroke and correlating the hypo‑ and hyperreflective OCT scattering areas with the location of activated microglia and astroglia. Angiogenesis, which was assessed using angiomaps, showed that the area of vessels in the ischemic center increased until day 7 ...

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    12. Evaluation of progressive retinal degeneration in Bipolar disorder patients over a period of 5 years

      Evaluation of progressive retinal degeneration in Bipolar disorder patients over a period of 5 years

      Purpose: To quantify visual and retinal changes in patients with bipolar disorder (BD) over 5 years, compared with controls. Methods: Thirty-eight patients with BD and 122 healthy subjects underwent visual acuity (VA) evaluation, contrast sensitivity vision testing (CSV) with the Pelli Robson and CSV 1000E tests, and retinal thicknesses measurement (ganglion cell layer - GCL- and retinal nerve fiber layer -RNFL-) using Spectralis Optical Coherence Tomography (OCT). All subjects were re-evaluated after 5 years. The relationship between progressive structural changes and disease duration was analysed. Results: Visual function parameters in BD patients remained unchanged during the follow up period. A progressive ...

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    13. Optical coherence tomography as retinal imaging biomarker of neuroinflammation/neurodegeneration in systemic disorders in adults and children

      Optical coherence tomography as retinal imaging biomarker of neuroinflammation/neurodegeneration in systemic disorders in adults and children

      The retina and the optic nerve are considered extensions of the central nervous system (CNS) and thus can serve as the window for evaluation of CNS disorders. Spectral domain optical coherence tomography (OCT) allows for detailed evaluation of the retina and the optic nerve. OCT can non-invasively document changes in single retina layer thickness and structure due to neuronal and retinal glial cells (RGC) modifications in systemic and local inflammatory and neurodegenerative diseases. These can include evaluation of retinal nerve fibre layer and ganglion cell complex, hyper-reflective retinal spots (HRS, sign of activated microglial cells in the retina), subfoveal neuroretinal ...

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    14. Research progress of optical coherence tomography and angiography in the diagnosis of Alzheimer's disease

      Research progress of optical coherence tomography and angiography in the diagnosis of Alzheimer's disease

      Alzheimer's disease(AD)is a progressive and irreversible neurological disease characterized by changes in neurons and blood vessels of the brain. Its etiology is unknown, and there is no feasible non-invasive technique for early diagnosis. Because the retina and the central nervous system have similar embryonic origins and physiological characteristics, an ophthalmic examination may provide a simple and non-invasive diagnostic method. Optical coherence tomography(OCT)can accurately measure the thickness of various tissue layers of the retina to assess degenerative changes of the retina. Optical coherence tomography angiography(OCTA)can provide high-resolution three-dimensional imaging, which can more directly detect ...

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    15. Choroidal changes in carotid stenosis patients after stenting detected by swept-source optical coherence tomography angiography

      Choroidal changes in carotid stenosis patients after stenting detected by swept-source optical coherence tomography angiography

      Background: Carotid artery stenosis (CAS) patients show reduced blood flow in the ophthalmic artery. This study aimed to assess the changes in the choriocapillaris and choroidal thickness in patients with unilateral carotid artery stenosis after carotid stenting using swept-source optical coherence tomography (SS-OCT)/swept-source optical coherence tomography angiography (SS-OCTA). Methods: Fifty-three mild to moderate CAS patients and 40 controls were enrolled in this study. All participants underwent digital subtraction angiography (DSA) and SS-OCT/SS-OCTAA imaging before and 4 days after carotid artery stenting. SS-OCTA was used to image and measure the perfusion of the choriocapillaris (mm2) while SS-OCT was used ...

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    16. Differentiation of primary central nervous system lymphoma from glioblastoma using optical coherence tomography based on attention ResNet

      Differentiation of primary central nervous system lymphoma from glioblastoma using optical coherence tomography based on attention ResNet

      Significance: Differentiation of primary central nervous system lymphoma from glioblastoma is clinically crucial to minimize the risk of treatments, but current imaging modalities often misclassify glioblastoma and lymphoma. Therefore, there is a need for methods to achieve high differentiation power intraoperatively. Aim: The aim is to develop and corroborate a method of classifying normal brain tissue, glioblastoma, and lymphoma using optical coherence tomography with deep learning algorithm in an ex vivo experimental design. Approach: We collected tumor specimens from ordinal surgical operations and measured them with optical coherence tomography. An attention ResNet deep learning model was utilized to differentiate glioblastoma ...

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    17. Optical coherence tomography in neurodegenerative disorders

      Optical coherence tomography in neurodegenerative disorders

      Structural imaging of the brain is the most widely used diagnostic tool for investigating neurodegenerative diseases. More advanced structural imaging techniques have been applied to early or prodromic phases, but they are expensive and not widely available. Therefore, it is highly desirable to search for noninvasive, easily accessible, low-cost clinical biomarkers suitable for large-scale population screening, in order to focus on making diagnoses at the earliest stages of the disease. In this scenario, imaging studies focusing on the structures of the retina have increasingly been used for evaluating neurodegenerative diseases. The retina shares embryological, histological, biochemical, microvascular and neurotransmitter similarities ...

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    18. Brain white matter morphological structure correlation with its optical properties estimated from optical coherence tomography (OCT) data

      Brain white matter morphological structure correlation with its optical properties estimated from optical coherence tomography (OCT) data

      A pilot post-mortem study identifies a strong correlation between the attenuation coefficient estimated from the OCT data and some morphological features of the sample, namely the number of nuclei in the field of view of the histological image and the fiber structural parameter introduced in the study to quantify the difference in the myelinated fibers arrangements. The morphological features were identified from the histopathological images of the sample taken from the same locations as the OCT images and stained with the immunohistochemical (IHC) staining specific to the myelin. It was shown that the linear regression of the IHC quantitative characteristics ...

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    19. Comparing retinal changes measured by optical coherence tomography in patients with schizophrenia and their siblings with healthy controls: Are retinal findings potential endophenotype candidates?

      Comparing retinal changes measured by optical coherence tomography in patients with schizophrenia and their siblings with healthy controls: Are retinal findings potential endophenotype candidates?

      Aim The aim of our study is to examine whether differences in retinal structure may reflect endophenotypes for schizophrenia by comparing thicknesses of retinal layers between patients with schizophrenia, their unaffected siblings, and healthy control groups and investigating the relationship between OCT findings and disease parameters. Material and methods 46 patients with schizophrenia, their 46 healthy siblings, and 46 age and gender-matched healthy controls were enrolled in the study and underwent spectral domain OCT (examinations to assess differences in peripapillary retinal nerve fiber layer (RNFL) thickness, ganglion cell layer (GCL)+ inner plexiform layer (IPL) thicknesses and macular volumes (MV) in ...

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    20. A multi-regression framework to improve diagnostic ability of optical coherence tomography retinal biomarkers to discriminate mild cognitive impairment and Alzheimer’s disease

      A multi-regression framework to improve diagnostic ability of optical coherence tomography retinal biomarkers to discriminate mild cognitive impairment and Alzheimer’s disease

      Background Diagnostic performance of optical coherence tomography (OCT) to detect Alzheimer’s disease (AD) and mild cognitive impairment (MCI) remains limited. We assessed whether compensating the circumpapillary retinal nerve fiber layer (cpRNFL) thickness for multiple demographic and anatomical factors as well as the combination of macular layers improves the detection of MCI and AD. Methods This cross-sectional study of 62 AD ( n  = 92 eyes), 108 MCI ( n  = 158 eyes), and 55 cognitively normal control ( n  = 86 eyes) participants. Macular ganglion cell complex (mGCC) thickness was extracted. Circumpapillary retinal nerve fiber layer (cpRNFL) measurement was compensated for several ocular factors. Thickness ...

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    21. Retinal imaging with optical coherence tomography in multiple sclerosis: novel aspects

      Retinal imaging with optical coherence tomography in multiple sclerosis: novel aspects

      Optical coherence tomography (OCT) is of increasing interest in the clinical assessment of multiple sclerosis (MS) patients beyond the scope of clinical studies. In this narrative review, we discuss novel changes of OCT parameters during acute optic neuritis and the disease course of MS patients. OCT images document the changes of retinal layers during an episode of acute optic neuritis and can therefore provide valuable insights into the pathophysiology. Moreover, MS patients show progredient thinning of retinal layers throughout the disease. The thinning is accelerated through relapses as well as disease progression without relapse. The OCT parameters are also associated ...

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    22. Differentiating Degenerative from Vascular Dementia with the Help of Optical Coherence Tomography Angiography Biomarkers

      Differentiating Degenerative from Vascular Dementia with the Help of Optical Coherence Tomography Angiography Biomarkers

      Alzheimer's disease and vascular dementia account for the majority of cases of cognitive decline in elderly people. These two main forms of dementia, under which various subtypes fall, are often overlapping and, in some cases, definitive diagnosis may only be possible post-mortem. This has implications for the quality of care and the design of individualized interventions for these patients. Optical coherence tomography angiography (OCTA) is a non-invasive imaging modality used to visualize the retinal layers and vessels which shows encouraging results in the study of various neurological conditions, including dementia. This review aims to succinctly sum up the present ...

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    23. Change in contrast sensitivity and OCT parameters in idiopathic intracranial hypertension

      Change in contrast sensitivity and OCT parameters in idiopathic intracranial hypertension

      Background: Deterioration in peripheral contrast sensitivity (CS) can be an indicator to detect progressive deterioration of visual function in patients with idiopathic intracranial hypertension (IIH). Objectives: The aim of this study was to evaluate the changes in central and peripheral CS and optical coherence tomography (OCT) parameters and in patients with IIH. Design and methods: In this pilot observational study, data of 20 eyes of 10 'treatment-naïve' IIH patients were analyzed. Detailed ocular examination was performed including CS assessment using both Pelli-Robson (PR) test and Spaeth-Richman Contrast Sensitivity Test (SPARCS) along with the OCT for macular and optic nerve ...

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