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1. Functional magnetic resonance imaging (fMRI) at 1.5 T was used to investigate the lateralization of prefrontal cortex activity during internal mental calculation in 16 human volunteers (8 right-handed and 8 left-handed). Subjects were asked to perform two different tasks: 1) a serial subtraction of prime numbers and 2) a control task in which they(More)
BACKGROUND AND PURPOSE Ultrasmall particles of iron oxide (USPIO) constitute a contrast agent that accumulates in cells from the mononuclear phagocytic system. In the CNS they may accumulate in phagocytic cells such as macrophages. The goal of this study was to compare USPIO-enhanced MR images with conventional T2-weighted images and gadolinium-enhanced(More)
Magnetic resonance imaging (MRI) is of great utility in diagnosis and monitoring of multiple sclerosis (MS). Axonal loss is considered the main cause of accumulating irreversible disability. MRI using ultrasmall-super-paramagnetic-iron-oxide (USPIO) nanoparticles is a new technique to disclose in vivo central nervous system (CNS) inflammatory lesions(More)
Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are: Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), Xenon-enhanced Computed Tomography (XeCT), Dynamic Perfusion-computed Tomography (PCT), Magnetic Resonance Imaging Dynamic Susceptibility Contrast (DSC), Arterial(More)
Cell-specific imaging has been proposed to increase the potential of magnetic resonance imaging (MRI) for tissue analysis. The hypothezis of the present work was that following intravenous injection of ultra-small particle iron oxide, a contrast agent that accumulates in mononuclear phagocyte cells, macrophages with iron burden would be detectable by MRI(More)
The neuronal network involved in a precise type of calculation procedure, mental subtraction, was investigated by means of functional magnetic resonance imaging. Two tasks were used requiring covert production of numbers: (1) with calculation; (2) without calculation. During the first task, activation was observed in the left dorsolateral prefrontal and(More)
RATIONALE AND OBJECTIVES In experimental allergic encephalomyelitis (EAE), central nervous system (CNS) macrophage imaging is achievable by MRI using AMI-227 an ultra-small particle iron oxide contrast agent at a dose of 300 micromol/kg Fe. The objective was to test the feasibility at the human recommended dose of 45 micromol/kg Fe. METHODS Two groups of(More)
Magnetization transfer (MT) provides post-gadolinium contrast improvement through decreasing the tissue signal. Our study had two aims: to analyse the effect of MT qualitatively and quantitatively in 13 patients, and to analyse in vitro the competition between two relaxation phenomena, dipole-dipole which is characteristic of MT and proton - electron which(More)
Ectopic ACTH-secreting tumours responsible for paraneoplastic Cushing's syndrome are invisible at radiography in about 50 percent of the cases. In this situation, the current attitude is to correct the hypercorticism and then embark on a regular morphological monitoring in search of the initial tumour with the purpose of removing it. We report the cases of(More)
We report a 17-year-old asymptomatic patient with a partially collapsed seventh cervical vertebra due to a haemangioma revealed by conventional radiographs performed for army enrollment. Given radiological evidence of aggressiveness, percutaneous vertebroplasty by injection of methyl methacrylate cement was performed to prevent complications. CT a year(More)