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V Dousset

Publications and source records attributed to V Dousset.

At least 37 records · Page 2Linked to original sources
PubMed1999

Dose and scanning delay using USPIO for central nervous system macrophage imaging.

RATIONALE AND OBJECTIVES: In experimental allergic encephalomyelitis (EAE), central nervous system (CNS) macrophage imaging is achievable by MRI using AMI-227 an ultra-small particle iron oxide contrast agent at a dose of 300 micromol/kg Fe. The objective was to test the feasibility at the human recommended dose of 45 micromol/kg Fe. METHODS: Two groups of EAE rats were tested with AMI-227 using 45 and 300 micromol/kg Fe respectively. Following i.v. injection of AMI-227, they were scanned after a delay of 4-6 and 20-24 h. RESULTS: With a high dose of AMI-227, all animals showed low signal intensity related to iron-loaded macrophages in the CNS. At low dose no abnormalities were found in the CNS. Furthermore, a delay of 4-6 h failed to demonstrate abnormalities even at high dose. CONCLUSIONS: Dose, scanning delay after administration and blood half-life are major parameters for T2* CNS macrophage imaging.

Animals↗
PubMed1999

Metastases from a pituitary adenoma: MRI.

Few cases of pituitary adenoma with metastases have been reported. We report a case with histologically benign intracranial and cauda equina metastases. We compare it to the others in the literature.

Adenoma↗
PubMed1999

Comparison of ultrasmall particles of iron oxide (USPIO)-enhanced T2-weighted, conventional T2-weighted, and gadolinium-enhanced T1-weighted MR images in rats with experimental autoimmune encephalomyelitis.

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 T1-weighted images in a model of experimental autoimmune encephalomyelitis (EAE). METHODS: Nine rats with EAE and four control rats were imaged at 4.7 T and 1.5 T with conventional T1- and T2-weighted sequences, gadolinium-enhanced T1-weighted sequences, and T2-weighted sequences obtained 24 hours after intravenous injection of a USPIO contrast agent, AMI-227. Histologic examination was performed with hematoxylin-eosin stain, Perls' stain for iron, and ED1 immunohistochemistry for macrophages. RESULTS: USPIO-enhanced images showed a high sensitivity (8/9) for detecting EAE lesions, whereas poor sensitivity was obtained with T2-weighted images (1/9) and gadolinium-enhanced T1-weighted images (0/9). All the MR findings in the control rats were negative. Histologic examination revealed the presence of macrophages at the site where abnormalities were seen on USPIO-enhanced images. CONCLUSION: The high sensitivity of USPIO for macrophage activity relative to other imaging techniques is explained by the histologic findings of numerous perivascular cell infiltrates, including macrophages, in EAE. This work supports the possibility of intracellular USPIO transport to the CNS by monocytes/macrophages, which may have future implications for imaging of human inflammatory diseases.

Animals↗
PubMed1999

Pathological correlates of magnetization transfer imaging abnormalities in animal models and humans with multiple sclerosis.

Magnetization transfer imaging is used in multiple sclerosis because of its sensitivity to tissue destruction; in particular, to demyelination. This sensitivity was established in animal models and human diseases. Studies in experimental auto-immune encephalomyelitis have shown that the magnetization transfer ratio is slightly decreased in inflammatory lesions of the central nervous system white matter without demyelination but is more decreased in demyelinated lesions according to the level of myelin loss. Toxic demyelination studies and human studies in progressive multifocal leukoencephalopathy have confirmed that pure moderate to severe demyelination can be monitored by this technique. Axon loss can also contribute to the decrease of this ratio. Magnetization transfer is a validated technique to assess tissue destruction in central nervous system white matter diseases.

Animals↗
PubMed1999

[Cerebral panthrombophlebitis in a paucisymptomatic patient].

In most cases, extensive cerebral venous thrombosis present themselves with a severe clinical outcome and poor prognosis. We present the case of a 59-years-old patient with a slight rather unrevealing symptoms but suffering from a cerebral thrombosis impacting on both superficial and deep venous system. The etiologic assessment revealed activated protein C resistance. Clinical evolution under systemic anticoagulation was prompt, with complete repermeabilization of the various venous structures.

Activated Protein C Resistance↗
PubMed1999

[Evaluation of the efficacy of foraminal infusions of corticosteroids guided by computed tomography in the treatment of radicular pain by foraminal injection].

PURPOSE: To evaluate the efficacy of foraminal steroid injections performed under CT guidance for the management of radicular pain. METHODS: Periganglionic infiltrations were performed in 160 patients with radicular pain refractory to medical treatment. Imaging showed either degenerative foraminal stenosis, herniated disk or postsurgical fibrosis. RESULTS: 102 patients (63.8%) had significant pain reduction. Pain relief was lasting in 68 (66.6%). CT showed the position of the needle tip, as well as the diffusion of the therapeutic compounds. CONCLUSION: We consider that CT-guided periganglionic steroid injections should be an integral part of the management strategy for radicular pain resistant to medical treatment.

Adrenal Cortex Hormones↗
PubMed1998

Early structural changes in acute MS lesions assessed by serial magnetization transfer studies.

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, and postgadolinium T1-weighted images for 9 to 12 months. In 15 new lesions, the MT ratio (MTR) was calculated retrospectively. RESULTS: In 13 lesions, a marked decrease in the MTR was present early during the first 2 months after the onset of the lesion and was followed by a variable increase. In two other lesions, the MTR progressively declined. CONCLUSIONS: These results suggest that major early structural changes compatible with demyelination and followed by remyelination and gliosis, or by continuous demyelination, occur in new MS lesions. The various MTR profiles provide in vivo confirmation of the current knowledge of the progression in MS lesions. Furthermore, MTR may be used to monitor in vivo drug efficacy in new MS lesions.

Adult↗
PubMed1998

Periganglionic foraminal steroid injections performed under CT control.

PURPOSE: The purpose of our study was to evaluate the efficacy of direct intraforaminal steroid injections into the periganglionic space in the treatment of radicular pain. METHODS: Periganglionic infiltrations were performed in 41 patients with acute or chronic radicular pain. Neuroradiologic imaging in all patients showed foraminal stenosis due to degenerative disorders or herniated disk. All injections were performed under CT control. RESULTS: Seventy percent of patients had significant pain reduction, with the greatest success (90% of patients) in those whose foraminal stenosis was due to degenerative disorders; 45% of patients with foraminal herniated disks had pain relief. CONCLUSION: Intraforaminal steroid injection is useful in the treatment of radicular pain, particularly in cases of foraminal degenerative stenosis.

Adult↗
PubMed1998

[Study of cortical atrophy with magnetic resonance imaging in corticobasal degeneration].

Corticobasal degeneration (C.B.D.) is a neurodegenerative disorder characterized mainly by an asymmetrical a kineto-rigid syndrome associated with fronto-parietal cortical signs, particularly apraxia. Conventional imaging even magnetic resonance imaging (M.R.I.) has often been considered as poorly contributive for the diagnosis of C.B.D. We retrospectively studied routinely performed M.R.I. scans of 15 patients presenting a clinical and metabolic (P.E.T/S.P.E.C.T.) syndrome characteristic of probable C.B.D. M.R.I. scans were assessed by 3 investigators, not aware of the clinically most affected side, taking into account M.R.I. technical parameters. We quantified, on each side, the cortical atrophy (frontal, parietal and temporal) and the white matter changes, by using the semi-quantified method of Victoroff et al. (1994). Abnormalities were considered if observed by at least 2 of the 3 investigators. Abnormalities were then correlated with the side initially and most severely affected. The most contributive findings were the asymmetric parietal atrophy (clinically correlated in 93 p. 100 of cases), asymmetric frontal atrophy (clinically correlated in 60 p. 100) and asymmetric dilatation of the lateral ventricles (clinically correlated in 60 p. 100). 80 p. 100 of affected subjects displayed at least 2 of these M.R.I. abnormalities. These results are in accordance with the metabolic and pathologic features of C.B.D. This study demonstrates that M.R.I. evaluation of the cortical atrophy asymmetry may contribute to the diagnosis of C.B.D.

Age of Onset↗
PubMed1998

[Fulminant orthochromatic leukodystrophy in an adult].

A 27-year-old man from Marocco developed a progressive dementia leading within a year to a mutic akinetic state. The course of the disease was also marked by epileptic seizures. MRI revealed diffuse white matter involvement. A frontal white matter brain biopsy was consistent with the diagnosis of orthochromatic leucodystrophy, i.e: presence of sudanophilic lipids and pigmented cells associated with myelin loss. Adult forms of orthochromatic leucodystrophy are very rare. Our case was characterized by a fulminant course.

Adult↗
PubMed1998

[Propriospinal myoclonus induced by relaxation and drowsiness].

Propriospinal myoclonus is a subtype of spinal myoclonus characterized by axial flexion or extension jerks, arrhythmic and prolonged muscle bursts with a pattern of activation consistent with a slow conduction within the propriospinal pathways. We describe a new idiopathic case of flexion propriospinal myoclonus occurring upon relaxation and drowsiness. This syndrome is to be added to the spectrum of movement disorders occurring during drowsiness.

Anticonvulsants↗
PubMed1997

Magnetization transfer imaging in vivo of the rat brain at 4.7 T: interpretation using a binary spin-bath model with a superLorentzian lineshape.

Proton magnetization transfer contrast (MTC) imaging, using continuous wave off-resonance irradiation, was performed on the rat brain in vivo at 4.7 Tesla. The observed MTC was studied in three different brain regions: the corpus callosum, the basal ganglia, and the temporal lobe. By systematically varying the offset frequency and the amplitude of the RF irradiation, the observed signal intensities for each region of interest were modeled using a system including free water and a pool of protons with restricted motions (R. M. Henkelman, X. Huang, Q. Xiang, G. J. Stanisz, SD Swanson, M. J. Bronskill, Magn. Res. Med. 29, 759 (1993)). Most of the relaxation parameters of both proton pools remained fairly constant for the three regions of interest, with a T2 value of about 9 micros for the immobilized protons, whereas the rate of exchange increased significantly from the temporal lobe to the corpus callosum. The optimal acquisition parameters for the improved MTC under steady-state saturation were found to be 2-10 kHz offset frequency and 500-800 Hz RF irradiation amplitude. Conversely, an irradiation amplitude of 3 kHz at an offset frequency of 12 kHz is required to minimize the direct effect of off-resonance irradiation. Such an approach could be extended to human brain imaging with the aim of characterizing tissue-specific disease.

Animals↗
PubMed1997

Improvement of post-gadolinium contrast with magnetization transfer.

Magnetization transfer (MT) provides post-gadolinium contrast improvement through decreasing the tissue signal. Our study had two aims: to analyse the effect of MT qualitatively and quantitatively in 13 patients, and to analyse in vitro the competition between two relaxation phenomena, dipole-dipole which is characteristic of MT and proton - electron which is characteristic of gadolinium. Contrast between lesion and white matter improved from 20.6 % before MT to 65.1 % after MT, enabling new lesions to be detected in two patients. The improvement was due mainly to the proton - electron effect of gadolinium rather than the dipole relaxation of MT. These results are in agreement with those in the literature. The existence of spontaneous high-signal induced by MT in the absence of gadolinium indicates that it is preferable to perform an MT sequence before and after administration of gadolinium.

Adolescent↗
PubMed1997

Cranial aneurysmal bone cysts presenting with raised intracranial pressure: report of two cases.

Aneurysmal bone cysts in the skull vault are reported in two patients 7 and 9 years old, who presented with vomiting and headaches caused by raised intracranial pressure. CT showed the cystic lesion in the diploë, with predominantly inward expansion. Fluid-fluid levels were seen on both CT and MRI; the latter also showed bleeding within the cyst. MR angiography showed compression of the superior sagittal sinus in the second case.

Bone Cysts, Aneurysmal↗
PubMed1997

Enzyme immunoassay for myelin basic protein in cerebrospinal fluid.

Myelin basic proteins (MBPs) are a set of proteins making up about 30% of the protein content of the central nervous system myelin. Four human isoforms have been identified. The most abundant is a highly conserved 18.5 kDa polypeptide. For this species, the amino acid sequence homologies between human and monkey or human and chick are 98.2% and 71.1%, respectively. As a consequence, there is a very good immunological cross-reactivity between the mammalian MBP. This protein has been extensively used to induce experimental allergic encephalomyelits (EAE) in numerous animals. The evolution of chronic EAE in animal is similar to that of multiple sclerosis (MS), a demyelinating human pathology, and chronic EAE is considered to be an animal model of MS. In demyelinating pathologies, MBP concentration in the cerebrospinal fluid (CSF) is considered to be a good marker of demyelination. MBP concentration, in biological fluids, is generally determined by radioimmunoassay (RIA). The RIA technique currently used is highly sensitive (0.1-2.5 ng/ml) but has the drawback of requiring the handling of radioactivity and frequent labelling of MBP. So we developed a new enzyme immunoassay (EIA) technique. Our technique has the same sensitivity as RIA, needs only small volumes of CSF (50 microliters) and the enzyme-labelled MBP tracer is stable for at least 12 months.

Alkaline Phosphatase↗