Right occipital cortex activation correlates with superior odor processing performance in the early blind.

Using functional magnetic resonance imaging (fMRI) in ten early blind humans, we found robust occipital activation during two odor-processing tasks (discrimination or categorization of fruit and flower odors), as well as during control auditory-verbal conditions (discrimination or categorization of fruit and flower names). We also found evidence for reorganization and specialization of the ventral part of the occipital cortex, with dissociation according to stimulus modality: the right fusiform gyrus was most activated during olfactory conditions while part of the left ventral lateral occipital complex showed a preference for auditory-verbal processing. Only little occipital activation was found in sighted subjects, but the same right-olfactory/left-auditory-verbal hemispheric lateralization was found overall in their brain.

Brain plasticity and cortical correlates of osseoperception revealed by punctate mechanical stimulation of osseointegrated oral implants during fMRI.

Purpose: Our aim was to unveil the cortical neural correlates of osseoperception, i.e. the tactile sensation perceived when loading a bone-anchored implant, by taking oral implants as a model.

A manually controlled new device for punctuate mechanical stimulation of teeth during functional magnetic resonance imaging studies.

Aim: To design a simple and affordable device that could apply standardized mechanical punctuate stimuli to trigger the periodontal mechanoreceptors during functional magnetic resonance imaging (fMRI).

Material And Methods: A new manually controlled device using von Frey monofilaments was tested on a phantom and on eight volunteers. Four block design paradigms with different timing were compared.

Corticospinal dysgenesis and upper-limb deficits in congenital hemiplegia: a diffusion tensor imaging study.

Objectives: Precision grasping critically relies on the integrity of the corticospinal tract as evidenced in congenital hemiplegia by the correlation found between corticospinal dysgenesis and hand-movement deficits. Therefore, corticospinal dysgenesis could be used to anticipate upper-limb deficits in young infants with congenital hemiplegia. However, most studies have quantified corticospinal dysgenesis by measuring the cross-sectional area of cerebral peduncles on T1 MRI, a measure biased by other structures present in the peduncles.

Comparative overview of brain perfusion imaging techniques.

Background And Purpose: Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are positron emission tomography, single photon emission computed tomography, Xenon-enhanced computed tomography, dynamic perfusion computed tomography, MRI dynamic susceptibility contrast, arterial spin labeling, and Doppler ultrasound. These techniques give similar information about brain hemodynamics in the form of parameters such as cerebral blood flow or cerebral blood volume.

Absolute CBF and CBV measurements by MRI bolus tracking before and after acetazolamide challenge: repeatabilily and comparison with PET in humans.

Bolus tracking magnetic resonance imaging (MRI) is a powerful technique for assessing cerebral perfusion, but its capability to measure absolute cerebral blood flow (CBF) and volume (CBV) values is still debated. To validate the MRI technique, absolute CBF and CBV values in healthy humans obtained by echo planar gradient echo MRI were compared to H(2)(15)O and (11)CO positron emission tomography (PET) before and after acetazolamide (ACZ) (n = 8) or saline (n = 4) administration. The repeatability of CBF and CBV measurements was moderate with both methods, and slightly lower with MRI than with PET.

Comparison of CT and three MR sequences for detecting and categorizing early (48 hours) hemorrhagic transformation in hyperacute ischemic stroke.

Background And Purpose: Our goal was to compare the sensitivity of CT and three MR sequences in detecting and categorizing early (48 hours) hemorrhagic transformation (HT) in hyperacute ischemic stroke.

Methods: Twenty-five consecutive patients with hyperacute ischemic stroke (<6 hours) without MR signs of cerebral bleeding at admission were included. Twenty-one underwent thrombolytic therapy.

MRI of hyperacute stroke in the AChA territory.

The purpose of our study was to derive from the anatomical literature an easy-to-use map of the brain areas supplied by the anterior choroidal artery (AChA) and to assess the correspondence between damage within the putative AChA areas and clinical symptoms. A thorough review of the literature led to the recognition of 16 anatomical areas which could be delineated on routine diffusion-weighted MR images. A database of 138 consecutive ischemic stroke patients examined with MRI less than 6 h after symptoms onset was thereafter processed in a retrospective way.

Functional reorganization of brain in children affected with congenital hemiplegia: fMRI study.

Using functional magnetic resonance imaging, the brain activation related to unilateral sequential finger-to-thumb opposition was studied in six children with a right congenital hemiplegia of cortical origin. They were compared to six age-matched controls. In the control group, movements with either hand asymmetrically activated the sensorimotor cortex and premotor areas in both cerebral hemispheres with a typical contralateral predominance.

Developmental aspects of language processing: fMRI of verbal fluency in children and adults.

We examined developmental differences, in location and extent of fMRI language activation maps, between adults and children while performing a semantic fluency task. We studied 29 adults and 16 children with echo planar imaging BOLD fMRI at 1.5 T using covert semantic verbal fluency (generation of words to categories compared to rest) using a block design.

A functional magnetic resonance imaging study of left hemisphere language dominance in children.

Background: Functional magnetic resonance imaging is a noninvasive method of assessing language dominance in a pediatric population.

Objective: To determine the pattern of receptive language lateralization in healthy children.

Design: We used functional magnetic resonance imaging to assess an auditory language task in 11 children (7 girls, 4 boys; mean age, 8.

Which MR-derived perfusion parameters are the best predictors of infarct growth in hyperacute stroke? Comparative study between relative and quantitative measurements.

Purpose: To compare predictors of infarct growth in hyperacute stroke from a retrospective review of various relative and quantitative parameters calculated at perfusion-weighted magnetic resonance (MR) imaging performed within 6 hours after ictus.

Materials And Methods: Fluid-attenuated inversion recovery and diffusion- and perfusion-weighted images were obtained in 66 patients. The initial infarct was delineated on diffusion-weighted images; the hemodynamic disturbance, on apparent mean transit time (MTT) maps; and the final infarct, on follow-up fluid-attenuated inversion recovery images.