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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)
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)
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)
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)
BACKGROUND AND PURPOSE Inflammatory multiple sclerosis (MS) lesions are characterized by microglia activation and infiltration of T cells, B cells, and macrophages across the blood-brain barrier (BBB). In the experimental autoimmune encephalomyelitis (EAE) rat model of MS, previous MR imaging investigations with a new contrast agent ultra-small-particle(More)
CT is the most effective examination technique for studying the evolution of ischemic attacks, but if performed within the first 3 weeks it does not allow prognosis of possible evolution towards necrosis. CBF measurement and vasoreactivity tests under Althesin do allow this prognosis. Thirty patients whose evolution was checked clinically and by repeated CT(More)
BACKGROUND Whether acute MS lesions are primarily inflammatory or demyelinative is unresolved. Our study examined acute MS lesions longitudinally by quantitative magnetization transfer (MT), an MRI technique that identifies tissue integrity and destruction. METHODS Four MS patients were studied by serial MRI including MT, conventional T2-weighted images,(More)
PURPOSE To study bystander demyelination in multiple sclerosis with an experimental in vivo model of toxic demyelination. METHODS Toxic demyelinating lesions were created in two monkeys by injection of lysophosphatidylcholine in the centrum semiovale. Follow-up was done clinically and with serial MR studies, including T2-weighted and gadolinium-enhanced(More)