PubMed Health⌕ Search

Biomedical subjects

V Dousset

Publications and source records attributed to V Dousset.

At least 73 records · Page 4Linked to original sources
PubMed1996

Asymptomatic cervical haemangioma treated by percutaneous vertebroplasty.

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 later showed no progression of the lesion. The patient remains asymptomatic.

Adolescent↗
PubMed1996

Magnetisation transfer ratios of contrast-enhancing and nonenhancing lesions in multiple sclerosis.

Magnetisation transfer (MT) is a recently introduced technique for assessing the water content of tissues in vivo and its relationship to macromolecules or membranes. It has been suggested that MT could provide indirect evidence of the characteristics of multiple sclerosis (MS) lesions (oedema, demyelination, or gliosis). Our aims were to characterise brain MS lesions and to compare the magnetisation transfer ratio (MTR) values of lesions with different patterns of contrast enhancement. In patients with MS we measured the MTR of 65 gadolinium-enhancing and 292 nonenhancing lesions. Using the equation published by Dousset et al. we studied 29 patients with clinically definite MS and 10 healthy controls. Lesions had significantly lower MT than the normal-appearing white matter of the patients or the normal white matter of healthy controls. There was no difference in the MTR of enhancing and nonenhancing lesions. Enhancement was homogeneous in 45 and ring-like in 20 lesions; MTR values were lower in the latter. These findings are presumably related to the differences in pathological features of enhancing (different amounts of proteins and inflammatory cells, oedema and demyelination) and nonenhancing (gliosis, demyelination and axonal loss) lesions.

Adult↗
PubMed1996

[MRI and Listeria monocytogenes rhombencephalitis].

Rhombencephalitidis is a serious form of brainstem inflammation, difficult to diagnose on the basis of clinical and laboratory findings alone. We describe the MR appearance of 3 cases of Listeria monocytogenes rhombencephalitidis and correlate the findings with clinical information. MR imaging is crucial for early diagnosis of this illness: patchy signal hyperintensity throughout the medulla and cerebellar peduncles on T2 weighted images, always in association with a hypointense dot; numerous gadolinium-enhanced microabcesses in the rhombencephalon. MR imaging is very useful for follow-up examinations.

Brain Abscess↗
PubMed1996

[Imaging of Erdheim-Chester disease].

Erdheim-Chester disease is a form of Histiocytosis which involves the adults and is distinct from Histiocytosis X. It is characterized by a constant diaphyseal and metaphyseal bone involvement predominating in the lower links. The diagnosis can readily be envisaged when the typical radiological findings are present. Bone involvement may be isolated and well tolerated, or can be associated with systemic involvement and a severe prognosis. We describe three cases of women aged 46, 50 and 73 years. One patient presented with isolated bone lesions, while the two others had a multiorgan localization. From the three cases and from an extensive review of the literature, we describe the spectrum of bone and visceral lesions that can be seen by imaging. The emphasis is put on lesions of the skeletal system, the retroperitoneum, the nervous system, and the pericardium. Furthermore, the relationships between Erdheim-Chester disease and Histiocytosis X are discussed.

Aged↗
PubMed1996

[Agenesis of the internal carotid artery associated with an aneurysm of the anterior communicating artery].

We report a case of agenesis of the internal carotid artery which was revealed by a subarachnoid hemorrhage. Angiography showed a ruptured aneurysm of the anterior communicating artery and unilateral absence of the left internal carotid artery. Both the left anterior and middle cerebral arteries were perfused from the right carotid artery via the anterior communicating artery. Absence of the left carotid canal was proved on bone CT. Such an association is discussed. An hemodynamic stress on a congenital defect of the cerebral arterial wall could be the origin of the aneurysm development.

Adult↗
PubMed1995

A magnetization transfer imaging study of normal-appearing white matter in multiple sclerosis.

We attempted to define the role of subtle changes in the normal-appearing white matter (NAWM) in the development of disability in multiple sclerosis (MS). Twenty-seven clinically definite MS patients with either relapsing-remitting or chronic-progressive courses and 10 sex- and age-matched controls entered the study. For each patient and control, we studied two NAWM areas in the frontal lobe with magnetization transfer imaging (MTI). For patients, we also calculated the MT ratios (MTRs) for three contiguous areas of NAWM progressively further from "isolated" lesions visible on conventional MRI. Frontal NAWM in MS patients had lower mean MTRs than the frontal white matter of the controls (p = 0.02). MTRs in the NAWM adjacent to isolated lesions increased with distance from them to the cortical gray matter (p = 0.04). This pattern was typical for patients with chronic-progressive MS whose MTRs in the first two regions of NAWM adjacent to lesions were lower than those of the same regions of patients with relapsing-remitting MS. This study confirms that there are alterations in the NAWM of MS patients and suggests that such changes might be relevant to the disability in MS.

Adult↗
PubMed1995

[Diagnosis of extrapontine myelinolysis preceding central pontine myelinolysis].

An MR study performed on a patient who presented a tetraplegia after liver transplantation, revealed bilateral hypersignal of internal globus pallidus on T2 weighted images. Diagnosis of extrapontine myelinolysis was proposed based on clinical presentation and lesions topography, although absence of natremic disorders. Confirmation of diagnosis was obtained on an MR study performed a month later, which demonstrated a pontine extension. Extrapontine myelinolysis can precede pontine involvement. Diagnosis of myelinolysis should be evoked although MR normal appearance of the pons.

Demyelinating Diseases↗
PubMed1995

Lysolecithin-induced demyelination in primates: preliminary in vivo study with MR and magnetization transfer.

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 T1-weighted images and measurement of magnetization transfer ratio, until the animals were killed at days 14 and 34, respectively. Light and electron microscopy analysis was compared with MR data. RESULTS: Interval measurement of magnetization transfer ratio during the course of the experiment revealed a maximum decrease at day 7 to day 8, associated with the greatest clinical manifestations. The lowest values of magnetization transfer ratio correlated with histopathologic findings of myelin and axon destruction. Magnetization transfer ratio measurements appear to be sensitive to macromolecular destruction and specifically to membrane disorganization. At no time was gadolinium enhancement observed in this model of toxic demyelination. CONCLUSION: Preliminary results of this study indicated that magnetization transfer is a good technique to follow in vivo matrix destruction in brain parenchyma lesions. The results suggest also that phases of toxic demyelination in multiple sclerosis might not show gadolinium enhancement. Differentiation between demyelinating activity and associated inflammation in multiple sclerosis lesions should be considered in further in vivo work.

Animals↗
PubMed1994

Correlation of spectroscopy and magnetization transfer imaging in the evaluation of demyelinating lesions and normal appearing white matter in multiple sclerosis.

Magnetization transfer imaging (MT) and localized proton spectroscopy (1H-MRS) were utilized in the evaluation of lesions (high signal abnormalities on T2-weighted images) and normal-appearing white matter (NAWM) in multiple sclerosis (MS). Eleven patients with a clinical diagnosis of MS were independently evaluated with both 1H-MRS and MT. The magnetization transfer ratio (MTR) of lesions was compared with the relative concentration of N-acetyl-aspartate (NAA) and a composite peak at 2.1 to 2.6 ppm termed "marker peaks." The MTR of white matter lesions in the MS patients was markedly decreased (6-34%; normal approximately 42%), and correlated well with increase in the marker peaks region (0.94-3.89). There was no correlation between the relative concentration of NAA and MTR. Increased resonance peaks in the 2.1 to 2.6 ppm range and marked decreases in MTR may be a relatively specific indicators of demyelination.

Adolescent↗
PubMed1994

Use of magnetisation transfer contrast to improve cerebral 3D MR angiography.

To improve 3D-time of flight (3D-TOF) magnetic resonance angiography, we used magnetisation transfer (MT) to increase the contrast between flowing blood and stationary tissues. With a 1.5 KHz off-resonance radio-frequency MT applied for 16 ms at a maximum power within specific absorption rate (SAR) limits, a 37% decrease in the signal of white matter was obtained, whereas the signal from flowing blood decreased by only 8%. An improvement in maximum intensity projection (MIP) image quality was obtained all MT-3DTOF studies on seven volunteers using progressively more powerful MT pulses. Routine clinical use of MT-3DTOF appears promising and can be achieved at any strength field.

Adult↗
PubMed1994

[Agyria-pachygyria and pachygyria in children. Contribution of imaging].

BACKGROUND: Lissencephaly (agyria-pachygyria) is a defect in migration of cerebral neurons resulting in failure of cortical gyri to develop. Progress in imaging techniques improves its diagnosis. POPULATION AND METHODS: The files of 17 patients (ten boys and seven girls), aged 7 months to 16 years, were retrospectively studied. The clinical picture consisted of mental retardation (17 patients), seizures (eight patients), facial dysmorphia (seven patients), axial hypotonia (four patients). CT scan was performed in 16 cases and MRI with T1 and T2 weighted images in all 17. RESULTS: The CT scan identified pachygyria in 12 cases. Cerebral calcifications were seen in four cases. MRI detected typical changes in all 17 cases: thickened cortex and gyri, loss of cortical white matter interdigitations, lack of operculisation of the sylvian fissure. Pachygyria was generalized (six patients) or localized (11 patients). Associated abnormalities were dysgenesis of corpus callosum in three patients, cerebellar hypoplasia in one, deep grey matter heterotopia in one; hypersignal of the white matter was identified on T2 weighted images in five patients. CONCLUSION: MR imaging permits precise analysis of abnormalities secondary to a defect in neuronal migration.

Adolescent↗
PubMed1992

Experimental allergic encephalomyelitis and multiple sclerosis: lesion characterization with magnetization transfer imaging.

Magnetization transfer imaging (MTI) was initially performed in normal guinea pigs and human volunteers. A magnetization transfer ratio (MTR) was calculated in the normal white matter and was found to be 42%-44%, with less than 2.5% variation, which indicates the high reproducibility of the measurement. MTI was then applied to an animal model of white matter disease, acute experimental allergic encephalomyelitis (EAE). In this model of EAE, pathologically proved lesions were edematous with essentially no demyelination. MTRs decreased slightly but significantly (5%-8%) compared with the MTRs of the same tissue region measured before the onset of the lesion [corrected]. Fifteen patients with multiple sclerosis (MS) also underwent MTI. In the 15 patients with MS, all lesions (209 plaques) had a significantly decreased MTR (average, 26%). The authors believe that demyelination produced the lower MTR, and, thus, lesions varied in transfer ratio on the basis of the extent of myelin loss. In patients with MS, particularly those with chronic and/or progressive MS, the MTR of the normal-appearing white matter was significantly decreased. The data suggest that calculated MTR obtained with in vivo MTI may enable differentiation of edema from demyelination, and that MTI can demonstrate white matter abnormalities that cannot be seen with standard spin-echo or gradient-echo magnetic resonance imaging.

Adult↗