MR spectroscopy of normal and impaired fetal brain

International audienceProton Magnetic Resonance Spectroscopy (MRS) is a non-invasive and quantitative method used to assess fetal brain metabolism during the 2nd and 3rd trimesters of gestation. Fetal brain MRS is performed in specialized centers using clinical MR systems operating at 1.5 or 3 T. Single voxel spectroscopy (SVS) with the Point RESolved Spectroscopy (PRESS) sequence (spin echo sequence) is currently the dominant method in this field. The major metabolic changes observed in the normal fetal brain are the increase of neuronal marker N-acetylaspartate and of creatine and phosphocreatine with advancing gestational age. Metabolic anomalies have been reported in cases of intrauterine restricted growth and cytomegalovirus infection

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

AbstractA 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

Respiratory‐triggered quantitative MR spectroscopy of the human cervical spinal cord at 7 T

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Creatine, Glutamine plus Glutamate, and Macromolecules Are Decreased in the Central White Matter of Premature Neonates around Term

International audiencePreterm birth represents a high risk of neurodevelopmental disabilities when associated with white-matter damage. Recent studies have reported cognitive deficits in children born preterm without brain injury on MRI at term-equivalent age. Understanding the microstruc-tural and metabolic underpinnings of these deficits is essential for their early detection. Here, we used diffusion-weighted imaging and single-voxel 1 H magnetic resonance spec-troscopy (MRS) to compare brain maturation at term-equivalent age in premature neonates with no evidence of white matter injury on conventional MRI except diffuse excessive high-signal intensity, and normal term neonates. Thirty-two infants, 16 term neonates (mean post-conceptional age at scan: 39.8±1 weeks) and 16 premature neonates (mean gesta-tional age at birth: 29.1±2 weeks, mean post-conceptional age at scan: 39.2±1 weeks) were investigated. The MRI/MRS protocol performed at 1.5T involved diffusion-weighted MRI and localized 1 H-MRS with the Point RESolved Spectroscopy (PRESS) sequence. Preterm neonates showed significantly higher ADC values in the temporal white matter (P<0.05), the occipital white matter (P<0.005) and the thalamus (P<0.05). The proton spectrum of the centrum semiovale was characterized by significantly lower taurine/H 2 O and macromole-cules/H 2 O ratios (P<0.05) at a TE of 30 ms, and reduced (creatine+phosphocreatine)/H 2 O and (glutamine+glutamate)/H 2 O ratios (P<0.05) at a TE of 135 ms in the preterm neonates than in full-term neonates. Our findings indicate that premature neonates with normal conventional MRI present a delay in brain maturation affecting the white matter and the thala-mus. Their brain metabolic profile is characterized by lower levels of creatine, glutamine plus glutamate, and macromolecules in the centrum semiovale, a finding suggesting altered energy metabolism and protein synthesis

Spectroscopie de la maturation cérébrale et de ses anomalies

National audienceL'imagerie par résonance magnétique (IRM) est la technique de choix pour l'exploration de la maturation cérébrale et de ses anomalies. La spectroscopie par résonance magnétique (SRM) est une technique de résonance magnétique nucléaire non invasive et spatialement localisée qui permet d'accéder au métabolisme intracérébral. Elle prend une place importante en neuroradiologie clinique au cours d'un examen par IRM standard. Cependant, les indications restent limitées à un petit groupe de pathologies, principalement les tumeurs, la souffrance cérébrale diffuse en particulier en période néonatale, et les maladies innées du métabolisme cérébral. Dans cet article sont revus les principaux noyaux étudiés en SRM, les méthodes d'acquisition et de post-traitement des données, les principaux métabolites détectables en SRM du proton et leurs variations au cours de la maturation cérébrale, et les principales applications cliniques dans la population pédiatrique

Assessment of neuronal dysfunction in benign multiple sclerosis: a sodium MRI study

International audienceAssessment of neuro-degenerative process in multiple sclerosis using sodium MRI. A study in a population of 135 subjects at different disability and disease duratio