Search results for "magnetic resonance image"

showing 4 items of 4 documents

Illumination Correction on MR Images

2006

Objective. An important artifact corrupting Magnetic Resonance Images is the rf inhomogeneity, also called bias artifact. This anomaly produces an abnormal illumination fluctuation on the image, due to variations of the device magnetic field. This artifact is particularly strong on images acquired with a device specialized on upper and lower limbs due to their coil configuration. A method based on homomorphic filtering aimed to suppress this artifact was proposed by Guillemaud. This filter has two faults: it doesnt provide an indication about the cutoff frequency (cf) and introduces another illumination artifact on the edges of the foreground. This work is an improvement to this method because i…

Artifact (error)Computer sciencebusiness.industryComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONHealth InformaticsFilter (signal processing)Critical Care and Intensive Care MedicineMagnetic Resonance ImagingCutoff frequencyMagnetic fieldAnesthesiology and Pain MedicineHomomorphic filteringBiasElectromagnetic coilIntensive careMagnetic Resonance Image MRI bias artifact illumination rf inhomogeneity homomorphic filter.Image Processing Computer-AssistedHumansKneeComputer visionArtificial intelligenceAnomaly (physics)businessAlgorithmsJournal of Clinical Monitoring and Computing
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Noise Filtering Using Edge-Driven Adaptive Anisotropic Diffusion

2008

This paper presents a method aimed to noise removal in MRI (Magnetic Resonance Imaging). We propose an improvement of Perona and Malik's anisotropic diffusion filter. In our schema, the diffusion equation of the filter has been modified to take into account the edges direction, This allows the filter to blur uniform areas, while it better preserves the edges. Both quantitative and qualitative evaluation is presented and the results are compared with other methods.

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniNoise Removal Magnetic Resonance Images Anisotropic Diffusion Brain MRIDiffusion equationNoise measurementComputer scienceAnisotropic diffusionWiener filterComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONFilter (signal processing)Edge-preserving smoothingMagnetic fieldAdaptive filtersymbols.namesakeComputer Science::Computer Vision and Pattern RecognitionsymbolsAlgorithm2008 21st IEEE International Symposium on Computer-Based Medical Systems
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High content and dispersion of Gd in bimodal porous silica: T2 contrast agents under ultra-high magnetic fields

2022

Silica-based UVM-7-type bimodal mesoporous materials with high gadolinium content (∞ ≥ Si/Gd ≥ 13) have been synthesized through a one-pot surfactant-assisted procedure from hydroalcoholic solution using a cationic surfactant as template, and starting from atrane complexes of Gd and Si as inorganic precursors. The novel synthetic pathway developed in the study preserves the UVM-7-type architecture while optimizing the dispersion of the Gd-guest species at the nanoscale and even at atomic level. It has been determined that the number of Gd atoms forming clusters is always less than 10. The behaviour under exposure to ultra-high magnetic fields reveals a significant increase in the transversa…

magnetic resonance microscopyMechanics of MaterialssilicaGeneral Materials ScienceGeneral ChemistrygadoliniumUNESCO::CIENCIAS TECNOLÓGICASCondensed Matter Physicsmesoporousmagnetic resonance image
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Individualized Template MRI Is a Valid and Reliable Alternative to Individual MRI for Spatial Tracking in Navigated TMS Studies in Healthy Subjects

2020

Objectives: Navigated transcranial magnetic stimulation (nTMS) provides significant benefits over classic TMS. Yet, the acquisition of individual structural magnetic resonance images (MRIindividual) is a time-consuming, expensive, and not feasible prerequisite in all subjects for spatial tracking and anatomical guidance in nTMS studies. We hypothesize that spatial transformation can be used to adjust MRI templates to individual head shapes (MRIwarped) and that TMS parameters do not differ between nTMS using MRIindividual or MRIwarped.Materials and Methods: Twenty identical TMS sessions, each including four different navigation conditions, were conducted in 10 healthy subjects (one female, 2…

primary motor cortextranscranial magnetic stimulationtemplate magnetic resonance imagesspatial transformationmotor evoked potentialsnavigationlcsh:Neurosciences. Biological psychiatry. Neuropsychiatrylcsh:RC321-571Frontiers in Human Neuroscience
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