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G Salamon

Publications and source records attributed to G Salamon.

At least 19 recordsLinked to original sources
PubMed2006

Diffusion tensor MRI shows abnormal brainstem crossing fibers associated with ROBO3 mutations.

Horizontal gaze palsy with progressive scoliosis (HGPPS) is caused by mutations in the ROBO3 gene, critical for the crossing of long ascending medial lemniscal and descending corticospinal tracts in the medulla. Diffusion tensor imaging in a patient with HGGPS revealed the absence of major pontine crossing fiber tracts and no decussation of the superior cerebellar peduncles. Mutations in the ROBO3 gene lead to a widespread lack of crossing fibers throughout the brainstem.

Adult↗
PubMed2005

The human cerebral cortex on MRI: value of the coronal plane.

The evaluation of different cortical areas of the cerebral cortex has been analyzed using MRI of 50 normal subjects without any neurological symptoms. This analysis has been made with different spin echo and gradient echo in T1 or T2 in three different planes: horizontal, sagittal and coronal. The most accurate plane to define important cortical areas such as Broca area, Wernicke area, temporal cortex at the level of the superior temporal sulcus, angular gyrus, supra marginal gyrus, hippocampal and parahippocampal cortices as well as that of the parieto or temporo-occipital areas is the coronal plane. Evidently it must be correlated with the other orthogonal planes. To be compared with the main Atlas of Neuroanatomy these sections must be perpendicular or parallel to the plane passing through the anterior and posterior commissures. MRI of patients with neurological disorders must have, as a routine, a series of MR sections performed in the coronal plane, as well as in horizontal and sagittal ones. The coronal plane is certainly the most precise to evaluate these areas involved in language, memory, visuo spatial or behavioral functions. It must be always compared with the rest of the neuroradiological examination and correlated with the clinical neurological signs.

Amygdala↗
PubMed2005

Analysis of the brain-stem white-matter tracts with diffusion tensor imaging.

The authors have reviewed the diffusion tensor imaging (DTI) of the brain stem in 19 subjects, consisting of 15 normal volunteers and four multi-system atrophy patients. The study was performed with 1.5 T MRI scanners. DTI was correlated with an automated program allowing superposition of the structural anatomy. Axial, sagittal, and coronal images demonstrated major white-matter fibers within the brain stem, including cortico-spinal tracts, transverse pontine fibers, and medial lemniscus. Smaller fibers, such as medial longitudinal fascicles and central tegmental tracts are difficult to visualize. To identify the anatomical orientation of the brain stem, white-matter fibers will help us understand the different functional disease processes, and DTI will play an important role for the evaluation of the different white matter fibers in the brain stem.

Adult↗
PubMed2004

[Magnetic resonance studies in Alzheimer's dementia. What routine scanning shows].

Magnetic resonance images of the brain acquired in relationship to the commissural plane have been analyzed in twenty cases classified as Probable Alzheimer's disease (Pr. AD). These examinations have been compared to normal aged matched subjects. All examinations have been made in strict correlation with the planes defined by Talairach and Tournoux (1988). The analysis of brain cortical damage was made by evaluating the sulci of the brain mainly on coronal sections correlated with simultaneous image review of the same area on the two other orthogonal planes. In Pr. AD, an asymmetric atrophic pattern was found mainly on the following areas: amygdaloid nucleus, para hippocampal gyrus, hippocampus, areas 22 and 21, temporal pole, insula, dorso frontal cortex, angular gyrus, superior parietal lobule. The primary motor and visual areas were normal in all cases.

Aged↗
PubMed2004

[Susceptibility weighted imaging. Theory and applications].

Susceptibility Weighted Imaging (SWI) is a new MR imaging technique using the BOLD effect (Blood Oxygen Level Dependent) and the differences of susceptibility between tissues. It is a 3D gradient echo, fully velocity compensated sequence. The echo time is chosen to maximize the signal cancellation in veins and a specific post-processing is applied using the phase images as a complementary source of contrast. It is very useful for the visualization of veins either normal or abnormal. It shows hemorrhage, even of small quantity, better than conventional gradient echo sequences. Its use is still limited by a long acquisition time and some remaining artifacts.

Blood↗
PubMed2001

A longitudinal study of callosal atrophy and interhemispheric dysfunction in relapsing-remitting multiple sclerosis.

OBJECTIVES: To determine if callosal atrophy and interhemispheric dysfunction can be detected in the early stages of relapsing-remitting multiple sclerosis (MS) and to evaluate their progression in relation to the disability and evolution of lesions seen on magnetic resonance imaging during a 5-year period. METHODS: We compared 30 patients who had clinically definite early-onset replasing-remitting MS and mild disability with control subjects. Regional and segmental callosal size and extent of white matter abnormalities on magnetic resonance imaging, as well as performance on tasks exploring interhemispheric transfer of motor, auditory, and sensory information were assessed. Patients with MS were evaluated at baseline and after 5 years. Physical disability was determined at both times using the Expanded Disability Status Scale score. RESULTS: Patients with MS were seen with significant callosal atrophy and functional impairment of interhemispheric transfer at baseline that worsened during the 5-year study. A significant correlation was found between the magnitude of disability and the severity of morphological and functional callosal involvement at baseline. This association persisted at year 5. Baseline clinical characteristics such as age and prestudy relapse rate were unrelated to callosal size or interhemispheric performance. However, the number of baseline T2-weighted lesions was correlated with callosal involvement and this relation persisted at year 5. CONCLUSION: Patients who had relapsing-remitting MS in the early stages of the disease and mild disability had significant callosal involvement that progressed over time. The relationship between disability, T2-weighted lesions load, and degree of morphological and functional callosal impairment confirm the potential value of using callosal dysfunction as a surrogate marker of disease progression in MS.

Adult↗
PubMed1999

MRI of the intracranial corticospinal tracts in amyotrophic and primary lateral sclerosis.

Our aim was to investigate the corticospinal tracts (CST) in motor neurone disease, using MRI, and to correlate findings with clinical data. We studied 31 patients with amyotrophic (ALS) and eight with primary lateral sclerosis (PLS). The signal from the CST was classified into four grades on T2-weighted images, and compared to T2-weighted images of 37 age-matched control subjects. No abnormalities were seen in the CST on T1-weighted images and were rarely evident on proton-density weighting. Variable high signal in the CST was found on T2-weighted images in 35 patients, and in 29 control subjects. Our grades 0 and 1 were more frequent in control subjects, grades 2 and 3 more frequent in patients. We found no correlation between the high signal and clinical data, including the duration of the illness. We therefore conclude that this technique is neither sensitive nor specific except in grade 3 which is quite specific for ALS. In half the patients we found atrophy of the superior parietal gyrus, which merits further study.

Adult↗
PubMed1999

[Divergent asymmetries of the temporo-parietal cortical areas: anatomo-functional correlations and evolutionary and developmental implications].

Human brains present a clear asymmetry of the postero-lateral cortical area, so called "planum temporale" (Geschwind and Levitsky). This asymmetry is on favour of the left brain. A similar asymmetry is observed on the parietal operculum. MRI studies of 37 healthy volunteers have shown a clear difference between individuals. Mixing the index of temporal and parietal asymmetry, the authors consider four types: the most frequent pattern concerns 90% of right handed. For the others, 10% there are left handed as right handed. On conclusion, planum as many asymmetry and opercular asymmetry can be divergent, and both canan to determines handedness.

Adolescent↗
PubMed1998

Contrast-enhanced magnetisation transfer MRI in metastatic lesions of the brain.

Our purpose was to compare prospectively the sensitivity of contrast-enhanced magnetisation transfer (MT) MRI and gradient-echo (GE) T1-weighted images in metastatic disease of the brain. We studied 52 patients with brain metastases, using conventional T1-weighted GE and MT spin-echo (SE) images after the same standard dose of gadolinium. Axial 5-mm reconstructions of GE data were compared with 5-mm MT images in the same plane. Metastases were counted independently by two neuroradiologists. In 12 patients (23%) MT imaging showed more metastases than GE images (P = 0.03). We detected 68 more metastases with the former technique.

Adult↗
PubMed1997

MRI of intracranial chordomas. Extent of tumour and contrast enhancement: criteria for differential diagnosis.

We present six proven cases of chordoma of the clivus studied by CT and MRI, with special attention to the extent of the tumour and to the signal intensity after intravenous gadolinium. MRI is the best technique for assessing the extent of the tumour but CT is important for showing osteolysis. Our aim was to determine differential diagnostic neuroradiological criteria. Reliable signs of chordoma of the skull base are: posterior extension to the pontine cistern; a lobulated, "honeycomb" appearance after gadolinium: the swollen appearance of the bone in the early stages; bone erosion on CT and frequent extension to critical structures such as the circle of Willis, cavernous sinuses and brain stem.

Adult↗
PubMed1996

Theoretical situation of brain white matter tracts evaluated by three-dimensional MRI.

An accurate knowledge of cerebral anatomy is important in order to evaluate the precise location of a cerebral lesion. Cortical structures are identified by knowledge of the adjacent gyri and sulci; however, white matter tracts are difficult to differentiate from one another due to the lack of clear anatomic landmarks. Therefore, even if MRI shows obvious white matter abnormalities, in some cases it is difficult accurately to localize the lesion. The purpose of this study is to evaluate the location of the main white matter tracts by using three-dimensional MR imaging. MRI study was performed by 1.5 Tesla (Signa: General Electric). Computer assisted analysis with Voxtool software (General Electric) was used to generate both surface brain and tomographic images. The exact anatomic basis of white matter signal abnormalities is important when analyzing patients with disconnective syndromes or neuropsychological deficits such as conduction aphasia, visuospatial deficit etc. This preliminary attempt at constructing a three-dimensional MRI white matter atlas of the brain may be helpful for evaluating the anatomico-clinical correlations in these patients, and also as teaching materials for the clinical (neurologic, neurosurgical), anatomic and radiographic disciplines.

Adult↗
PubMed1995

Diverging asymmetries of temporo-parietal cortical areas: a reappraisal of Geschwind/Galaburda theory.

The general theory on the biological foundations of cerebral dominance formulated in 1985 by Geschwind and Galaburda entirely relies on a postulated causal relationship between anatomical asymmetry of the planum temporale and functional lateralization of the human brain, but does not take into account asymmetry of another cortical region, the parietal operculum. In 40 normal volunteers whose handedness was specified by the Edinburgh Handedness Inventory, we assessed asymmetries of these two regions on MRI sagittal scans. For both measurements, a significantly larger leftward asymmetry was found in the 24 consistent right-handers compared to the 16 non-right-handers. Moreover, the combination, for each subject, of the two indices of asymmetry, yielded four different subtypes between which handedness distribution significantly differed. We conclude that planum temporale and parietal operculum asymmetries may be divergent and that their convergence is strongly associated with right-handedness. Functional and developmental implications of these findings are discussed by reference to the Geschwind/Galaburda theory.

Adolescent↗
PubMed1995

Mutism and auditory agnosia due to bilateral insular damage--role of the insula in human communication.

We report a case of transient mutism and persistent auditory agnosia due to two successive ischemic infarcts mainly involving the insular cortex on both hemispheres. During the 'mutic' period, which lasted about 1 month, the patient did not respond to any auditory stimuli and made no effort to communicate. On follow-up examinations, language competences had re-appeared almost intact, but a massive auditory agnosia for non-verbal sounds was observed. From close inspection of lesion site, as determined with brain resonance imaging, and from a study of auditory evoked potentials, it is concluded that bilateral insular damage was crucial to both expressive and receptive components of the syndrome. The role of the insula in verbal and non-verbal communication is discussed in the light of anatomical descriptions of the pattern of connectivity of the insular cortex.

Adult↗
PubMed1995

Functional magnetic resonance imaging at 1.5 T during sensorimotor and cognitive task.

Functional activations of the human brain cortex were observed with a standard 1.5-tesla MR imaging system using a long time echo fast low-angle shot sequence. Neural activation increases regional cerebral blood flow resulting in increased capillaries and venous blood oxygenation. Processing requires adapted algorithms because the time course of intensity signal showed fluctuations of the baseline. The use of a 'follow-up' method to generate activation maps is proposed. Brain activation was detected in striate cortex during photic stimulation and in sensorimotor areas while subjects were moving their hands. In mental imagery tasks, we observed a primary and secondary visual cortex activation during memory recall of the flashing light. Motor ideation showed an activation of the rolandic areas.

Adult↗
PubMed1994

[Spinal dural fistula with peri-medullar venous drainage].

Clinical and neuroradiological findings of 8 patients with a spinal dural arteriovenous fistula are reviewed. Disturbance of micturition or defecation and weakness of the legs were always present and the most frequent initial symptom was a progressive spastic paraparesis. Duration of symptoms before diagnosis was 2 years. Lumbar puncture showed elevation of proteins and myelography demonstrated dilated perimedullar posterior veins. In every case, magnetic resonance imaging of the spinal cord (T2- weighted images) revealed intramedullary high signal intensity of the conus medullaris and selective angiography confirmed the site of the dural fistula. Each patient was treated with endovascular method consisting in liquid adhesive embolization (0.2 cc of N-butyl cyanoacrylate) with hyperselective catheterism of the dorsospinal artery. Embolization procedure was successful in 6 cases with large improvement of leg weakness and partial regression of disturbed micturition and defecation. The pathophysiological mechanisms explaining the clinical signs are discussed.

Aged↗
PubMed1994

[Functional cerebral neuro-imaging at 1.5 Tesla. The results of visual, sensorimotor and auditory stimulations].

Functional activation of the cerebral cortex can be observed with a standard 1.5 Tesla MRI magnet. We used a repeated FLASH 2D one-section sequence with a long echo (TE = 60 ms) and a small passing band. Modification of regional cerebral oxygenation due to neurone activation seems to be the main source of contrast. Sensorimotor stimulation was effected by an unusual mobilization of the fingers. Visual stimulation was performed by intermittent lightings at a frequency of 8 Hz. Auditory stimulation relied on listening to speech sounds. Signal increases were localized on the cerebral cortex with precise anatomico-functional correlation. Using a clinical 1.5 Tesla magnet requires an adequate treatment of data. Thus, stimulated cerebral activity can be portrayed by MRI therapy opening a new way for anatomico-functional cerebral studies.

Acoustic Stimulation↗
PubMed1994

Location of hand function in the sensorimotor cortex: MR and functional correlation.

PURPOSE: To determine the location of hand function in the sensorimotor cortex using MR and positron emission tomography imaging studies. METHODS: Anatomic and physiological methods were used for this study. Anatomic study was based on the MR analysis of 22 subjects. The length of the sensorimotor cortex was measured in the axial and sagittal planes. Physiologic study was based on the positron emission tomography studies of 4 subjects. Each of the studies was correlated with MR. RESULTS: We found that the superior genu of the central sulcus corresponds to hand function in the sensorimotor cortex. This level may prove useful for any clinical correlations or for surgery. CONCLUSIONS: From this study, the hand function area in the sensorimotor cortex is easily understood with its characteristic shape in axial MR scan. The comparison of MR and positron emission tomography data clearly show anatomic correlations. This may be applied to the functional mapping of the pathologic studies in the sensorimotor cortex regions.

Adult↗