1,720,991 research outputs found
Evidence of subtle gray-matter pathologic changes in healthy elderly individuals with nonspecific white-matter hyperintensities
No full textA functional MRI study of cortical activations associated with object manipulation in patients with MS
No full textPrevious functional magnetic resonance imaging (fMRI) studies of simple motor tasks have shown that in patients with multiple sclerosis (MS), there is an increased recruitment of several regions part of a complex sensorimotor network. These studies have suggested that this might be the case because patients tend to activate, when performing a simple motor task, regions that are usually activated in healthy subjects during the performance of more complex tasks due to the presence of subcortical structural damage. In this study, we tested this hypothesis by comparing the patterns of cortical activations during the performance of two tasks with different levels of complexity from 16 MS patients and 16 age- and sex-matched controls. The first task (simple) consisted of flexion-extension of the last four fingers of the right hand, and the second task (complex) consisted of object manipulation. During the simple task, MS patients had, when compared to controls, more significant activations of the supplementary motor area (SMA), secondary sensorimotor area, posterior lobe of the cerebellum, superior parietal gyros (SPG), and inferior frontal gyros (IFG). These three latter regions are part of a fronto-parietal circuit, whose activation occurs typically in the contralateral hemisphere of healthy subjects during object manipulation, as shown also by the present study. During the performance of the complex task, MS patients showed an increased bilateral recruitment of several areas of the fronto-parietal circuit associated with object manipulation, as well of several other areas, which were mainly in the frontal lobes. This study confirms that some of the regions that are activated by MS patients during the performance of simple motor tasks are part of more complex pathways, recruited by healthy subjects when more complex and difficult tasks have to be performed. (C) 2003 Elsevier Inc. All rights reserved
Proton magnetic resonance spectroscopy in Parkinson's disease and progressive supranuclear palsy
No full textAbstract
Objectives-Proton magnetic resonance spectroscopy (H-1-MRS) localised to the lentiform nucleus, was carried out in eight patients with idiopathic Parkinson's disease and five patients with progressive supranuclear palsy. The aim of the study was to assess the concentration of N-acetyl-aspartate (NAA), creatine and phosphocreatine (Cr), and choline containing compounds (Cho) in the putamen and globus pallidus of these patients.
Methods-Peak ratios obtained from patients were compared with those from nine healthy age matched controls.
Results-NAA/Cho and NAA/Cr ratios were reduced significantly in patients with progressive supranuclear palsy.
Conclusion-These results suggest an NAA deficit, due to neuronal loss, in the lentiform nucleus of these patients. H-1-MRS is a non-invasive technique that can provide useful information concerning striatal neuronal loss in the basal ganglia of patients with parkinsonian syndromes
Convexal subarachnoid hemorrhage and acute ischemic stroke: a border zone matter?
Full text linkBackground Convexal subarachnoid hemorrhage (c-SAH) is an infrequent condition with variable causes. c-SAH concomitant
to acute ischemic stroke (AIS) is even less frequent, and the relationship between the two conditions remains unclear.
Methods Between January 2016 and January 2018, we treated four patients who were referred to our stroke unit with ischemic
stroke and concomitant nontraumatic c-SAH. The patients underwent an extensive diagnostic workup, including digital subtraction angiography (DSA).
Results All four patients developed acute focal neurological symptoms with restricted MRI diffusion in congruent areas. In three of
the patients, infarcts were in a border zone between the main cerebral arteries and c-SAH was nearby. The fourth patient showed a
small cortical infarct, and c-SAH was in a border zone territory of the contralateral hemisphere. An embolic source was discovered or
strongly suspected in all cases. One patient was treated with intravenous thrombolysis, but this treatment was not related to c-SAH.
None of the four patients showed microbleeds or further cortical siderosis, thus excluding cerebral amyloid angiopathy. In addition,
DSA did not show signs of vasculitis, reversible cerebral vasoconstriction syndrome, or intracranial arterial dissection.
Conclusions We proposed the embolism or hemodynamic changes of the border zone arterioles as a unifying pathogenetic
hypothesis of coexisting c-SAH and AIS
Volumetric and voxel based study of diffusion-perfusion mismatch in the acute phase of the ischemic stroke
No full textA preliminary diffusion tensor and magnetization transfer magnetic resonance imaging study of early-onset multiple sclerosis
No full textBackground: Early-onset multiple sclerosis (MS) typically has a more favorable course than adult-onset disease. Objective: To assess the extent of microscopic tissue damage in the brain and cervical cord of patients with early-onset MS. Design: During a single magnetic resonance imaging session, images of the brain and spinal cord were obtained using diffusion tensor and magnetization transfer magnetic resonance imaging. Patients: We studied 13 patients with early-onset MS and 10 healthy volunteers. Results: Compared with control subjects, patients with early-onset MS showed only a slight increase of the average mean diffusivity of the normal-appearing brain tissue. Conclusion: The relatively modest central nervous system damage detected in these patients might explain why early-onset MS typically has a more favorable clinical course than adult-onset MS
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