[Cerebral metabolism in patients with cognitive disorders: a combined MRS and PET study]. / Tserebral'nyi metabolizm u bol'nykh s kognitivnymi rasstroistvami: kombinirovannoe issledovanie s primeneniem magnitno-rezonansnoi spektroskopii i pozitronno-émissionnoi tomografii.

AIM: Magnetic resonance spectroscopy (MRS) allows studying the content of many metabolites in neural tissue in vivo. There are numerous studies devoted to the MRS data analysis in Alzheimer's disease (AD), but their results are contradictory. Thus, it is rational to compare the data obtained with MRS and positron emission tomography (PET) with fluorodeoxyglucose (FDG), which allows evaluating the brain functional state. In this paper, the authors compared MRS data in AD and mild cognitive impairment (MCI) with the cerebral glucose metabolism changes according to FDG PET. MATERIAL AND METHODS: Multivoxel proton MRS of the supraventricular area was performed in patients with AD (n=16) and MCI (n=14). The following metabolites ratios were evaluated: NAA/Cr, Cho/Cr, NAA/Cho (NAA - N-acetylaspartate, Cr - creatine, Cho - choline). All patients underwent neurological examination, assessment of cognitive status and PET with FDG. RESULTS: A decrease in NAA/Cr and Cho/Cr ratios in the supraventricular white matter and medial cortex in both hemispheres was observed in AD patients. In the MCI group, NAA/Cr ratio were decreased only in left white matter adjusting to the parietal cortex. Positive correlations of NAA/Cr and Cho/Cr ratios with cognitive status, as well as the cerebral glucose metabolism rate according to the PET data in frontal, parietal, temporal and cingulate cortex were revealed. CONCLUSION: The decrease in the NAA/Cr ratio in the supraventricular white matter and the medial cortex in AD and the correlation of this index with the results of cognitive tests and cerebral glucose metabolism suggest that it can be of diagnostic significance, reflecting the severity of cognitive impairment. In this case, the NAA/Cr ratio should be evaluated taking into account the changes in concentrations of both metabolites (NAA and Cr) in dementia.

[Regional metabolic changes of supraventricular tissue in patients with relapsing-remitting and secondary-progressive multiple sclerosis]. / Regionarnye osobennosti metabolizma strukturno neizmenennogo veshchestva supraventrikuliarnykh prostranstv golovnogo mozga pri remittiruiushchem i vtorichno-progressiruiushchem tipakh techeniia rasseiannogo skleroza.

AIM: To evaluate and compare the intensity of changes in a regional meta-analysis in relapsing-remitting and secondary-progressive multiple sclerosis (RRS and SPMS). MATERIAL AND METHODS: The results of longitudinal studies of multiple sclerosis (MS) using positron emission tomography, magnetic resonance spectroscopy and diffusion tensor imaging are presented. RESULTS: In MS, metabolic changes precede the structural ones. The markers of neuronal and axonal dysfunction (a decrease in NAA/Cr ratios in the white and grey matters, without the structural changes) are recorded in the early stages. The metabolic changes in the grey matter were recorded mostly in the middle frontal gyrus and posterior cingulate cortex. With the increase of duration and severity of MS, the metabolic changes spread to the other regions of supraventricular areas. The distribution of degeneration zones is related to MS course. CONCLUSION: There is substantial evidence on the irreversible damage of neurons in the medial prefrontal cortex in SPMS that confirms the vulnerability of the frontal cingulate gyrus in MS.