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F Nicoli

Publications and source records attributed to F Nicoli.

At least 19 recordsLinked to original sources
PubMed2003

Metabolic counterpart of decreased apparent diffusion coefficient during hyperacute ischemic stroke: a brain proton magnetic resonance spectroscopic imaging study.

BACKGROUND AND PURPOSE: Recent studies have shown that the brain ischemic area defined by the map of decreased apparent diffusion coefficient (ADC) obtained by diffusion-weighted imaging (DWI) during the first hours of ischemic stroke includes a significant part of ischemic penumbra. We hypothesize that the misjudgment of the final infarct size by ADC mapping may be related to a restricted ability of DWI to capture variations in the intensity of cellular suffering. In an attempt to characterize metabolically the hypoperfused brain parenchyma, we studied the relationship between ADC values and brain metabolic parameters measured by proton MR spectroscopic imaging (SI). METHODS: Six patients with hyperacute ischemic stroke were explored within the first 7 hours after onset with the use of a MR protocol including T2*-weighted MRI, DWI, SI, perfusion-weighted imaging, and MR angiography. RESULTS: This study demonstrates, for the first time, a wide gradient of ischemia-related metabolic anomalies within the abnormal area delineated by DWI during hyperacute ischemic stroke. In the narrow range of decreased mean ADC values (0.60 to 0.40 x 10(-9) m2 x s(-1)), a 33% decrease in mean ADC is associated with a 122% increase in lactate/N-acetyl aspartate ratio. Mean ADC values never fall below 0.40 x 10(-9) m2 x s(-1) within the severely affected ischemic tissue, while SI still detects a large metabolic heterogeneity inside areas showing similar decreased mean ADC values close to this threshold. CONCLUSIONS: Our results indicate that the region of very low mean ADC values observed during hyperacute ischemic stroke contains areas of various tissue damage intensity characterized by SI in relation to different stages of cellular metabolic injury. This observation may explain why ADC mapping does not reliably predict final infarct size.

Acute Disease↗
PubMed2001

Regional metabolite levels of the normal posterior fossa studied by proton chemical shift imaging.

MR spectroscopy of the posterior fossa is pitted with numerous technical difficulties. It is, however, of great clinical interest in the study of the degenerative diseases and tumors of this area. We have developed a method to perform 2D CSI of this area, by using a sagittal slice and a careful positioning of outer volume saturation. We performed this acquisition in 30 healthy volunteers to determine the normal metabolic ratios in five voxels of this area (mesencephalon, pons, medulla oblongata, vermis, cerebellar white matter). The main technical difficulty was magnetic field inhomogeneity in the lower brainstem generated by dental alloys. However, 88% of the voxels were of sufficient quality to be analyzed. The statistically significant regional variations were a higher NAA/Cr ratio in the pons than in the medulla oblongata, higher Cho/Cr in the pons than in the mesencephalon and higher Cho/Cr in the cerebellar white matter than in the vermis. We conclude that 2D CSI of the brainstem, although technically delicate can be performed in most patients.

Brain↗
PubMed2001

[Applications of magnetic resonance spectrometry (MRS) in the study of metabolic disturbances affecting the brain in alcoholism].

The purpose of this article is to provide an overview of the current applications of magnetic resonance spectroscopy (MRS) to the investigation of cerebral metabolism in alcoholic patients. The specific metabolic changes associated with the intoxication process (tolerance, dependance), abstinence and alcohol-related diseases (alcoholic encephalopathy, cirrhosis, Gayet-Wernicke's encephalopathy, Marchiafava-Bignami syndrome) are described.

Alcohol-Induced Disorders, Nervous System↗
PubMed2001

[Epileptic seizures, hemiplegia and hyperglycemia: late discovery of a localized cortical dysplasia].

A 56-year-old woman was hospitalized with a right hemiplegia and aphasia evoking a cerebral infarction. In fact the neurologic deficits were of post-ictal origin, secondary to a partial epilepsy which began a few weeks before, at the same time as a polyuria-polydipsia syndrome revealing diabetes mellitus. This case illustrates the possibility for a partial epilepsy to occur in relation with a nonketotic hyperglycemia. If in most of those cases there is no underlying cortical lesion, in some observations the hyperglycemia is associated with an infarction. In our case the MRI revealed another type of lesion: a cortical dysplasia in form of a unilateral micropolygyria with a perisylvian distribution centered around the insula. The discovery of a cortical dysplasia at such an age is very unusual.

Cerebral Cortex↗
PubMed1998

Further assignment of resonances in 1H NMR spectra of cerebrospinal fluid (CSF).

A number of previously unidentified 1H NMR signals detected in CSF spectra of patients with various neurological and metabolic diseases are assigned to metabolites, drugs and drug excipients. Two-dimensional 1H NMR spectroscopy (COSY and J-resolved) is employed to resolve resonances which are hidden by superimposed peaks in one-dimensional spectra. Assignments obtained by making use of 2-D techniques, and of a 1-D 1H NMR data base created for ca. 150 authentic compounds, enable us to clarify the nature of complex signal patterns found in crowded spectral regions of CSF such as the aliphatic methyl region at ca. 1.0 ppm.

Alcohols↗
PubMed1998

Experimental protocol for clinical analysis of cerebrospinal fluid by high resolution proton magnetic resonance spectroscopy.

High resolution magnetic resonance spectroscopy (MRS) of cerebrospinal fluid (CSF) is a non-destructive analytical method which allows rapid and simultaneous detection of molecules involved in intermediary and oxidative metabolic pathways. We developed a protocol suitable for routine MRS analysis of lyophilized CSF samples. This procedure guarantees sample integrity, from CSF collection to spectrum acquisition. MRS analysis of blood serum was included in our protocol as a complementary method to CSF analysis. This protocol can contribute to establish MRS of CSF as a new analytical tool to better understand the metabolic processes involved in neurological diseases.

Adult↗
PubMed1997

Brain proton magnetic resonance spectroscopy in HIV-related encephalopathy: identification of evolving metabolic patterns in relation to dementia and therapy.

Proton MRS has proved useful in the early diagnosis of HIV-related encephalopathy. The modifications of brain metabolism in HIV-related encephalopathy can be classified according to different metabolic patterns (Vion-Dury J et al. CR Acad Sci 1994;317:833-840). The present study describes the relative occurrence of these patterns and evaluates their evolution under zidovudine treatment. We have examined 112 HIV patients--35 neuroasymptomatic patients and 77 patients with ADC (AIDS dementia complex)--with localized proton MRS, using the PRESS 135-msec sequence. We have found the same metabolic modifications in N-acetylaspartate and choline-containing compounds as described in the literature. In addition, 14% of HIV patients with normal MRI displayed abnormal MRS, whatever their neurological status. The MRS-added diagnostic value in neuroasymptomatic patients reaches 30 %. The occurrence of undifferentiated (modification of NAA/Cho ratio only) and Cho (mainly an increase in choline signal) patterns is not significantly different in neuroasymptomatic and ADC patients. The NAA pattern (mainly a significant loss of NAA) is more frequent in ADC patients. Only ADC patients display the double pattern (with a significant increase in choline signal and a significant loss of NAA). Quantitated cerebral atrophy (bifrontal ratio) is related to the occurrence of NAA loss (in NAA and double patterns). An MRS follow-up study of 11 HIV patients showed that the clinical outcome was favorable after a 1000-mg/day zidovudine treatment in patients displaying an NAA pattern whereas this treatment had no effect on the patients displaying the Cho pattern. Consequently, MRS appears to be of great interest in predicting responsiveness to antiretroviral drugs and detecting early any resistance to treatment.

AIDS Dementia Complex↗
PubMed1997

Cerebral metabolic alterations in human immunodeficiency virus-related encephalopathy detected by proton magnetic resonance spectroscopy. Comparison between sequences using short and long echo times.

RATIONALE AND OBJECTIVES: The aim of this study is to evaluate comparatively the metabolic information afforded by proton magnetic resonance (MR) spectroscopy with stimulated-echo acquisition mode (STEAM) (echo time [TE], 20 mseconds) and point-resolved spectroscopy sequence (PRESS) (TE, 135 mseconds) spectra in HIV-related encephalopathy. METHODS: Sixty-three human immunodeficiency virus (HIV) patients and 8 controls were examined by single-voxel proton MR spectroscopy at 1.5 tesla, using both PRESS (TE, 135 mseconds) and STEAM (TE, 20 mseconds) sequences performed during the same MR examination, in the same volume of interest. Cerebral atrophy was quantitated using bicaudate ratio (BCR) and bifrontal ratio (BFR). RESULTS: With the STEAM (TE, 20 mseconds) spectra, mean N-acetylaspartate (NAA)/choline (Cho) and NAA/creatine and phosphocreatine (Cr-PCr) ratios are reduced in acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) patients but not in neuroasymptomatics. The proportion of inositol signal is increased, that of NAA decreased in ADC patients. NAA/Cho and NAA/ Cr-PCr mean values measured with PRESS (TE, 135 mseconds) spectra are significantly reduced in ADC and neuroasymptomatic patients. Bifrontal ratio only correlates with NAA/Cr-PCr and NAA/Cho measured on the PRESS spectrum. PRESS (TE, 135 mseconds) spectra allow a definition of different metabolic patterns in HIV-related encephalopathy. At last, no correlation has been found between the NAA raw signals measured on the PRESS (TE, 135 mseconds) and STEAM (TE, 20 mseconds) spectra obtained in the same MR examination. CONCLUSIONS: STEAM (TE, 20 mseconds) spectra provide more metabolic information-namely an evaluation of glial-neuronal status-than PRESS (TE, 135 mseconds) spectra, which afford a metabolic classification of the HIV-related encephalopathy. Because both sequences afford a similar diagnostic gain, MR spectroscopy examination probably requires spectrum acquisition with both sequences.

AIDS Dementia Complex↗
PubMed1997

[Neurosyphilis with multiple gummas and AIDS. Report of a case].

The incidence of neurosyphilis has been increasing since AIDS has appeared but acute gummatous necrotizing progression is so far exceptional. We report a second case of "quaternary neurosyphilis" in a 29-year-old patient without serologic nor CT scan evidence of treponema. Diagnosing neurosyphilis is particularly difficult in HIV-1 infected patients, specially in spirochetes-poor injuries.

Acquired Immunodeficiency Syndrome↗
PubMed1996

A multicenter proton magnetic resonance spectroscopy study of neurological complications of AIDS.

Human immunodeficiency virus (HIV) infection as seen in Europe and the United States has predominantly been contracted through male homosexual sex or intravenous drug abuse. In infected subjects, the brain is frequently affected both clinically and neuropathologically. The aim of this multicenter study has been to evaluate the value of single-voxel proton magnetic resonance spectroscopy (MRS) in the assessment of the neurological complications of acquired immunodeficiency syndrome (AIDS). MRS (voxel size = 8 ml, TR/TE = 1600/135 msec) was performed in 137 HIV-1-seropositive patients and 64 healthy controls without risk factors at three clinical MR sites operating at 1.5 T. The first result of this multicenter trial is that good reproducibility of results among participating sites was found. This demonstrates the reliability and robustness of MRS in the study of in vivo brain metabolism. In HIV patients, there was no significant correlation between metabolite ratios of brain detected by MRS and CDC grouping of patients or CD4 count. In contrast, the variations of brain metabolite ratios (NA/Cr, NA/Cho, and Cho/Cr) were related to the occurrence of encephalopathy, brain atrophy, or diffuse white matter lesions. There was no significant difference in brain metabolites between male homosexual AIDS patients and male intravenous drug user AIDS patients, whatever their neurological status (neurosymptomatic or neuroasymptomatic). Thus, the mode of transmission of HIV infection does not appear to affect the cerebral changes observed in the proton spectra from AIDS patients. Because of its ease of implementation and high information content, single-voxel proton MRS is likely to play a significant role in the evaluation of HIV-related encephalopathies.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Cerebrospinal fluid metabolic profiles in multiple sclerosis and degenerative dementias obtained by high resolution proton magnetic resonance spectroscopy.

We have analyzed the cerebrospinal fluid (CSF) of 19 patients with multiple sclerosis (MS), 12 patients with degenerative dementia and 17 control patients using in vitro high resolution proton magnetic resonance spectroscopy (MRS) at 400 MHz. The CSF metabolic profile is slightly modified in MS patients (increased lactate and fructose concentrations, decreased creatinine and phenylalanine concentrations) and is not correlated with the intensity of the intrathecal inflammation. Proton MRS of CSF does not differentiate relapsing-remitting MS and primary progressive MS. We have not detected any specific abnormal resonance in native or lyophilized CSF. The CSF metabolic profile of demented patients is much more altered (increased concentration of lactate, pyruvate, alanine, lysine, valine, leucine-isoleucine, tyrosine, glutamine) and is in agreement with a brain oxidative metabolism impairment as already described in Alzheimer's disease. Unassigned abnormal but non specific or constant resonances have been detected on MR spectra of demented patients. CSF inositol concentration is also increased in the CSF of patients with Alzheimer's disease. In vitro high resolution proton MRS of the CSF constitutes a new and original way to explore CSF for the differential and/or early diagnosis of dementias, as a complement to in vivo proton cerebral MRS.

Adult↗
PubMed1995

Localised proton magnetic resonance spectroscopy in X-linked adrenoleukodystrophy.

We have performed localised proton magnetic resonance spectroscopy (MRS) of the brain on four patients with X-linked adrenoleukodystrophy (X-ALD). The spectrum is characterised at the beginning of the disease by a decrease in N-acetylaspartate and phosphocreatine-creatine content. Choline is strongly increased, and lactate can be detected in some cases. A proton signal from the CH2 groups borne by free intracellular very long chain fatty acids can also be observed. Later in the disease, the levels of all metabolites, in particular NAA, decrease significantly. The progression of neurometabolism documented by MRS correlates well with MRI and clinical progression on follow-up study. In one case, the metabolic profile recorded by proton MRS was abnormal before any change occurred on MRI. Proton MRS of the brain might be the method of choice for monitoring patients with X-ALD, to screen presumed cases and to study the effects of treatment.

Adolescent↗
PubMed1994

[Marchiafava-Bignami disease: interhemispheric disconnection, Balint syndrome, spontaneously favourable outcome].

We report a new case of Marchiafava-Bignami disease with favourable outcome. This case is particular on several scores. The interhemispheric disconnection syndrome was associated with Balint's syndrome, and this had apparently never been reported in this context previously. Despite the intensity and diffusion of white matter lesions in both hemispheres, and in the absence of vitamin treatment, the clinical and neuroradiological (CT, MRI) improvement occurred early and rapidly. This course, similar to that of toxic drug withdrawal, suggested that this was not a process of vitamin deficiency. Data from the literature indicate that a wide extension of corpus callosum lesions to the semi-ovale centre has a poor vital and functional prognosis. Our case shows that this is not always correct and that the appearance of intralesional necrosis and cavitation is not the rule. We consider that the most reliable factor of poor prognosis seems to be an initial coma.

Adult↗
PubMed1994

Localized brain proton MRS metabolic patterns in HIV-related encephalopathies.

We have examined 9 healthy volunteers and 63 HIV-patients (16 asymptomatic patients and 47 patients with clinical AIDS-dementia complex, ADC) by magnetic resonance spectroscopy (MRS) and imaging (MRI) on a Siemens Magnetom SP63 (1.5 T). Proton MRS of the brain was performed at 63 MHz using the PRESS sequence (echo time = 135 ms, TR = 1.6 s). Four main results have been found: (1) HIV-related encephalopathy induces significant modifications of brain metabolism analyzed by MRS and the most sensitive metabolic parameter is the N-acetyl-aspartate/Choline ratio, (2) the correlation between MRS and MRI is good in 75% of patients, (3) in 4 of the 16 neuro-asymptomatic patients (i.e. 25%) a metabolic encephalopathy was found while MRI was still normal, and (4) MR spectra describe 3 different pathological metabolic patterns in the brain of HIV patients. Two patterns might correspond to the two entities of HIV-induced lesions i.e. HIV encephalitis and HIV-related progressive leukoencephalopathy.

AIDS Dementia Complex↗
PubMed1993

CSF and serum metabolic profile of patients with Huntington's chorea: a study by high resolution proton NMR spectroscopy and HPLC.

We studied both cerebrospinal fluid (CSF) and serum of 11 patients suffering from Huntington's disease (HD) and 12 control subjects by combining high resolution proton NMR spectroscopy and HPLC. NMR spectroscopy analysis of the CSF shows a significant increase (60%) in pyruvate concentration in HD patients. No unexpected molecules were detected. Glutamate, glutamine, aspartate, proline and GABA levels were found unchanged in the CSF of HD patients, using HPLC analysis. Conversely, a significant increase (30%) in the CSF level of glycine was detected. These observations are in agreement with the metabolic hypothesis of HD physiopathogenesis. In addition, the protocol combining NMR spectroscopy and HPLC provides a straightforward evaluation of brain metabolic status and blood-brain-barrier function.

Amino Acids↗