Rat lung MRI using low-temperature prepolarized helium-3

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MRI measurement of the functional blood flow changes in a large superficial vein draining the motor cortex

In this study, phase‐contrast MR techniques are applied in order to measure the blood flow changes induced by a motor task in a large superficial vein draining the motor cortex. The measurements were applied to six healthy volunteers, in motor rest conditions and during performance of a motor task. The latter consisted of sequential finger‐to‐thumb opposition. The task was actually executed and mentally simulated. Significant blood flow increases were found when changing from from mental simulation to actual execution of the motor task (increases ranging between 1.6 and 10.3 ml/min, i.e. 9% and 45%, respectively) and from resting conditions to actual execution of the motor task (increases ranging between 1.7 and 14.0 ml/min, i.e. 32% and 72%, respectively)

Functional MRI of the human brain: Predominance of signals from extracerebral veins

This study demonstrates the predominance of extracerebral vascular signals in gradient-echo functional magnetic resonance imaging of motor activity at 1.5 Tesla. The demonstration is based upon a novel experimental approach. Maximum intensity projection images are derived from a large set of contiguous 2D functional MR images, and compared with MR angiograms obtained from the volume covered by the set of functional MR images. The comparison shows that the hyperintensities in the functional MR images cover extensive areas, which can be superimposed with a number of veins in the MR angiograms. These results should trigger a general caution in interpretation of the observations in 1.5 Tesla functional MRI. © Rapid Communications of Oxford Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Possible involvement of primary motor cortex in mentally simulated movement

The role of the primary motor cortex (M1) during mental simulation of movement is open to debate. In the present study, functional magnetic resonance imaging (fMRI) signals were measured in normal right-handed subjects during actual and mental execution of a finger-to-thumb opposition task with either the right or the left hand. There were no significant differences between the two hands with either execution or simulation. A significant involvement of contralateral M1 (30% of the activity found during execution) was detected in four of six subjects. Premotor cortex (PM) and the rostral part of the posterior SMA were activated bilaterally during motor imagery. These findings support the hypothesis that motor imagery involves virtually all stages of motor control

1H mrs of human brain abscesses in vivo and in vitro

Five patients, each with a brain abscess, were examined by means of 1H MR spectroscopic imaging in vivo. The aspirated pus was analyzed in vitro by means of 1D and 2D COSY 1H MRS. In addition to resonance lines from compounds (lactate, alanine and lipids) often found in the spectra from intracranial tumors, resonance lines were detected from a number of markers of infectious involvement (acetate, succinate, and various amino acids). These results suggest that 1H MRS in vivo might contribute in establishing noninvasively a differential diagnosis between brain abscess and tumor. Copyright © 1995 Wiley‐Liss, Inc. A Wiley CompanySCOPUS: ar.jFLWNAinfo:eu-repo/semantics/publishe