Search results for " MRI"
showing 10 items of 290 documents
Evidence for early, non-lesional cerebellar damage in patients with multiple sclerosis: DTI measures correlate with disability, atrophy, and disease …
2015
Background: Common symptoms of multiple sclerosis (MS) such as gait ataxia, poor coordination of the hands, and intention tremor are usually the result of dysfunctionality in the cerebellum. Magnetic resonance imaging (MRI) has frequently failed to detect cerebellar damage in the form of inflammatory lesions in patients presenting with symptoms of cerebellar dysfunction. Objective: To detect microstructural cerebellar tissue alterations in early MS patients with a “normal appearing” cerebellum using diffusion tensor imaging (DTI). Methods: A total of 68 patients with relapsing–remitting MS (RRMS) and without cerebellar lesions and 26 age-matched healthy controls were admitted to high-resolu…
Reproducibility of multiphase pseudo-continuous arterial spin labeling and the effect of post-processing analysis methods
2015
Arterial spin labeling (ASL) is an emerging MRI technique for non-invasive measurement of cerebral blood flow (CBF). Compared to invasive perfusion imaging modalities, ASL suffers from low sensitivity due to poor signal-to-noise ratio (SNR), susceptibility to motion artifacts and low spatial resolution, all of which limit its reliability. In this work, the effects of various state of the art image processing techniques for addressing these ASL limitations are investigated. A processing pipeline consisting of motion correction, ASL motion correction imprecision removal, temporal and spatial filtering, partial volume effect correction, and CBF quantification was developed and assessed. To fur…
Lithium and GSK3-β promoter gene variants influence white matter microstructure in bipolar disorder
2013
Lithium is the mainstay for the treatment of bipolar disorder (BD) and inhibits glycogen synthase kinase 3-beta (GSK3-beta). The less active GSK3-beta promoter gene variants have been associated with less detrimental clinical features of BD. GSK3-beta gene variants and lithium can influence brain gray matter structure in psychiatric conditions. Diffusion tensor imaging (DTI) measures of white matter (WM) integrity showed widespred disruption of WM structure in BD. In a sample of 70 patients affected by a major depressive episode in course of BD, we investigated the effect of ongoing long-term lithium treatment and GSK3-beta promoter rs334558 polymorphism on WM microstructure, using DTI and …
Abnormal BAEP and internal auditory canal MRI in intracranial hypotension
2017
Intracranial hypotension (IH) is a treatable condition due to cerebrospinal fluid leak, characterised by variable clinical and MRI findings.1 Positional headache, neck stiffness, hearing changes with subdural fluid collection, enhancement of meninges, engorgement of venous structures and brain sagging are among the most frequent clinical and MRI findings. Typical abnormalities are found in 68%–85% of patients1. Hearing alterations (ranging from misperception to severe hearing loss) are known clinical symptoms of IH.1 The mechanism involves secondary perilymph depression due to patency of the cochlear aqueduct, inducing a compensatory expansion of the endolymphatic compartment, decreasing ba…
Voxel based analyses of diffusion tensor imaging in Fabry disease
2007
Background: Fabry disease (FD) is a lysosomal storage disorder that is associated with marked cerebrovascular disease. Conventional MRI shows an extensive load of white matter lesions (WMLs) already at an early stage in FD. Objective: Investigator independent and sensitive quantification of brain structural changes in clinically affected men and women with FD. Methods: The authors performed a voxel-based analysis of diffusion tensor images (DTI) in 25 FD patients and 20 age-matched normal controls. Results: DTI revealed significant increases of cerebral white matter diffusivity (MD) in FD patients that were pronounced in the periventricular white matter. Even the subgroup of patients withou…
Diffusion weighted magnetic resonance imaging in the diagnosis of reversible ischaemic deficits of the brainstem
2002
Objectives: To evaluate the sensitivity of diffusion weighted magnetic resonance imaging (MRI) for the diagnosis of clinically suspected reversible ischaemic deficits of the brainstem. Methods: A total of 158 consecutive patients presenting with acute signs of brainstem dysfunction were investigated using EPI diffusion weighted MRI within 24 hours of the onset of symptoms. High resolution T1 and T2 weighted imaging was performed as a follow up after a median of six days Results: Fourteen of the 158 patients had a complete clinical recovery within 24 hours (transitory ischaemic attack (TIA)), and 19 patients recovered in less than one week (prolonged reversible neurological deficit (RIND)). …
Topodiagnostic implications of hemiataxia: An MRI-based brainstem mapping analysis
2007
The topodiagnostic implications of hemiataxia following lesions of the human brainstem are only incompletely understood. We performed a voxel-based statistical analysis of lesions documented on standardised MRI in 49 prospectively recruited patients with acute hemiataxia due to isolated unilateral brainstem infarction. For statistical analysis individual MRI lesions were normalised and imported in a three-dimensional voxel-based anatomical model of the human brainstem. Statistical analysis revealed hemiataxia to be associated with lesions of three distinct brainstem areas. The strongest correlation referred to ipsilateral rostral and dorsolateral medullary infarcts affecting the inferior ce…
Unusual MRI findings in an immunocompetent patient with EBV encephalitis: a case report.
2011
Abstract Blackground It is well-known that Epstein-Barr virus (EBV) can affect the central nervous system (CNS). Case presentation Herein the authors report unusual timely Magnetic Resonance Imaging (MRI) brain scan findings in an immunocompetent patient with EBV encephalitis. Diffusion weighted MRI sequence performed during the acute phase of the disease was normal, whereas the Fast Relaxation Fast Spin Echo T2 image showed diffuse signal intensity changes in white matter. The enhancement pattern suggested an inflammatory response restricted to the brain microcirculation. Acyclovir and corticosteroid therapy was administered. After three weeks, all signal intensities returned to normal and…
Diffusion-weighted MRI of the lung with hyperpolarized helium-3: A study of reproducibility
2005
Purpose To determine the reproducibility of several parameters of the ADC measurement by calculating the scan-to-scan intrasubject variability. Materials and Methods Measurements were performed using a gradient-echo sequence with a bipolar gradient for diffusion weighting (b = 3.89 sec/cm2). Five patients with pulmonary emphysema, and six healthy-lung volunteers were included in the study. Images were acquired after inspiration of 3He during a single inspiratory breath-hold. To assess the reproducibility, the measurement was performed twice (time between measurements = 20 minutes) without repositioning the subjects. Analysis was performed on the basis of region-of-interest (ROI) analysis an…
Motor abnormalities and basal ganglia in first-episode psychosis (FEP)
2020
AbstractBackgroundMotor abnormalities (MAs) are the primary manifestations of schizophrenia. However, the extent to which MAs are related to alterations of subcortical structures remains understudied.MethodsWe aimed to investigate the associations of MAs and basal ganglia abnormalities in first-episode psychosis (FEP) and healthy controls. Magnetic resonance imaging was performed on 48 right-handed FEP and 23 age-, gender-, handedness-, and educational attainment-matched controls, to obtain basal ganglia shape analysis, diffusion tensor imaging techniques (fractional anisotropy and mean diffusivity), and relaxometry (R2*) to estimate iron load. A comprehensive motor battery was applied incl…