Search results for " magnetic resonance imaging"
showing 10 items of 452 documents
Exploring Frequency-Dependent Brain Networks from Ongoing EEG Using Spatial ICA During Music Listening
2020
Recently, exploring brain activity based on functional networks during naturalistic stimuli especially music and video represents an attractive challenge because of the low signal-to-noise ratio in collected brain data. Although most efforts focusing on exploring the listening brain have been made through functional magnetic resonance imaging (fMRI), sensor-level electro- or magnetoencephalography (EEG/MEG) technique, little is known about how neural rhythms are involved in the brain network activity under naturalistic stimuli. This study exploited cortical oscillations through analysis of ongoing EEG and musical feature during freely listening to music. We used a data-driven method that co…
Clinical neurophysiology and imaging of nerve injuries: preoperative diagnostic work-up and postoperative monitoring
2015
Peripheral nerve injuries are a heterogeneous group of lesions that may occurs secondary to various causes. Several different classifications have been used to describe the pathophysiological mechanisms leading to the clinical deficit, from simple and reversible compression-induced demyelination, to complete transection of nerve axons. Neurophysiological data localize, quantify, and qualify (demyelination vs . axonal loss) the clinical and subclinical deficits. High-resolution ultrasound can demonstrate the morphological extent of nerve damage, fascicular echotexture (epineurium vs . perineurium, focal alteration of the cross-section of the nerve, any neuromas, etc. ), and the surrounding t…
Hidden Markov random field model and Broyden–Fletcher–Goldfarb–Shanno algorithm for brain image segmentation
2018
International audience; Many routine medical examinations produce images of patients suffering from various pathologies. With the huge number of medical images, the manual analysis and interpretation became a tedious task. Thus, automatic image segmentation became essential for diagnosis assistance. Segmentation consists in dividing the image into homogeneous and significant regions. We focus on hidden Markov random fields referred to as HMRF to model the problem of segmentation. This modelisation leads to a classical function minimisation problem. Broyden-Fletcher-Goldfarb-Shanno algorithm referred to as BFGS is one of the most powerful methods to solve unconstrained optimisation problem. …
Physics, Techniques and Review of Neuroradiological Applications of Diffusion Kurtosis Imaging (DKI)
2016
In recent years many papers about diagnostic applications of diffusion tensor imaging (DTI) have been published. This is because DTI allows to evaluate in vivo and in a non-invasive way the process of diffusion of water molecules in biological tissues. However, the simplified description of the diffusion process assumed in DTI does not permit to completely map the complex underlying cellular components and structures, which hinder and restrict the diffusion of water molecules. These limitations can be partially overcome by means of diffusion kurtosis imaging (DKI). The aim of this paper is the description of the theory of DKI, a new topic of growing interest in radiology. DKI is a higher or…
Hippocampal reversible lesions in a case of transient global amnesia
2018
We report the case of 55-year-old man that after an emotional stress showed retrograde and anterograde amnesia with impairment of orientation in space and time but undisturbed consciousness. A neurological examination excluded other neurological signs or symptoms. The amnesic syndrome resolved spontaneously within 24 hours and the hypothesis of transient global amnesia was placed. Brain CT scan and conventional MRI sequences did not show any relevant pathological findings but diffusion-weighted imaging (DWI) showed two millimetric bright spot of restricted diffusion in the right hippocampus; in a brain MRI follow-up those findings were no more appreciable. The diagnosis of transient global …
Breast dynamic contrast-enhanced-magnetic resonance imaging and radiomics: State of art
2020
Breast cancer represents the most common malignancy in women, being one of the most frequent cause of cancer-related mortality. Ultrasound, mammography, and magnetic resonance imaging (MRI) play a pivotal role in the diagnosis of breast lesions, with different levels of accuracy. Particularly, dynamic contrast-enhanced MRI has shown high diagnostic value in detecting multifocal, multicentric, or contralateral breast cancers. Radiomics is emerging as a promising tool for quantitative tumor evaluation, allowing the extraction of additional quantitative data from radiological imaging acquired with different modalities. Radiomics analysis may provide novel information through the quantification…
Lesion load may predict long-term cognitive dysfunction in multiple sclerosis patients
2015
Background: Magnetic Resonance Imaging (MRI) techniques provided evidences into the understanding of cognitive impairment (CIm) in Multiple Sclerosis (MS). Objectives: To investigate the role of white matter (WM) and gray matter (GM) in predicting long-term CIm in a cohort of MS patients. Methods: 303 out of 597 patients participating in a previous multicenter clinical-MRI study were enrolled (49.4% were lost at follow-up). The following MRI parameters, expressed as fraction (f) of intracranial volume, were evaluated: cerebrospinal fluid (CSF-f), WM-f, GM-f and abnormal WM (AWM-f), a measure of lesion load. Nine years later, cognitive status was assessed in 241 patients using the Symbol Dig…
Chameleonic appearance of caseous calcification of the mitral valve – still a problem for its appropriate management
2021
According to the research literature, the caseous calcification of the mitral annulus (CCMA) is a rare variant of the mitral annulus calcification (MAC) entity, described mostly in elderly women. The aim of this study was to present the case of a 53-year-old female patient with caseous calcification of the mitral valve annulus and posterior cusp, which was diagnosed as papillary fibroelastoma. An echo-dense and quasi-homogeneous tumoral mass, measuring 1.6/1.4 cm, at the level of the posterior mitral ring was detected by echocardiographic examination, as well as by cardiac magnetic resonance imaging (MRI). Histopathological analysis revealed fibrous connective tissue with myxoid areas, hyal…
Antagonism between brain regions relevant for cognitive control and emotional memory facilitates the generation of humorous ideas
2021
Abstract The ability to generate humor gives rise to positive emotions and thus facilitate the successful resolution of adversity. Although there is consensus that inhibitory processes might be related to broaden the way of thinking, the neural underpinnings of these mechanisms are largely unknown. Here, we use functional Magnetic Resonance Imaging, a humorous alternative uses task and a stroop task, to investigate the brain mechanisms underlying the emergence of humorous ideas in 24 subjects. Neuroimaging results indicate that greater cognitive control abilities are associated with increased activation in the amygdala, the hippocampus and the superior and medial frontal gyrus during the ge…
Personality modulates brain responses to emotion in music: Comparing whole-brain and regions-of-variance approaches
2019
AbstractWhether and how personality traits explain the individual variance in neural responses to emotion in music remains unclear. The sparse studies on this topic report inconsistent findings. The present study extends previous work using regions of variance (ROVs) as regions of interest, compared with whole-brain analysis. Fifty-five subjects listened to happy, sad, and fearful music during functional Magnetic Resonance Imaging. Personality was measured with the Big Five Questionnaire. Results confirmed previous observations of Neuroticism being positively related to activation during sad music, in the left inferior parietal lobe. In an exploratory analysis, Openness was positively relat…