N. A. Semenova

1 H-MRS and MEGA-PRESS pulse sequence in the study of balance of inhibitory and excitatory neurotransmitters in the human brain of ultra-high risk of schizophrenia patients

The MEGA-PRESS pulse sequence was used for determination of overlapping signals in the 1H-MRS spectra of the human brain. For the first time, the balance of GABA glutamate/glutamine concentrations was estimated quantitatively in the human brain of patients with ultra-high risk of schizophrenia. It was found that GABA concentration and GABA/GLX ratios were significantly reduced in the left frontal lobe of UHR subjects.

The effect of neurostimulation on the intracellular concentrations of proton-containing metabolites and macroergic phosphates in the brain cortex upon schizophrenia according to the data from 1H and 31P magnetic resonance spectroscopy

The effect of neuroactivation on the concentrations of direct (phosphocreatine, PCr; adenosine triphosphate, ATP) and indirect (N-acetylaspartate, NAA) participants of energy metabolism and the intracellular pH values in the activated brain loci in health and upon early-stage schizophrenia is considered. Single-voxel 1H and 2D 31P magnetic resonance spectroscopy methods were used. The neuroactivation areas were localized according to the data from functional magnetic resonance imaging (fMRI). The NAA level after a short stimulus in the premotor cortex in schizophrenic patients remained unchanged, while the health group showed a reversible decrease in this parameter even 12 s after stimulus presentation. The long video stimulation has no effect on the contents of PCr and ATP in the visual cortex upon schizophrenia, while the analogous action on the health brain causes a decrease in the PCr level with the ATP level being constant. In the absence of neurostimulation, all measured indices were identical in both schizophrenic patients and control group.

The use of1H-NMR spectroscopy for predicting the efficiency of neoadjuvant chemotherapy of breast cancer

The pool of low-molecular-weight metabolites was studied in patients with breast cancer by high-resolution1H-NMR spectroscopy. In order to predict the efficiency of treatment, mathematical regression analysis was carried out with consideration for some clinical morphological characteristics of patients, chemotherapy protocols, and the degree of therapeutic pathomorphosis. The efficiency of drug therapy was largely determined by metabolic status of tumors in untreated patients with breast cancer.

Effect of Cell Therapy on Metabolite Content in Brain Structures of Children with Consequences of Severe Brain Injury: 1H Magnetic Resonance Spectroscopy Study

The effect of intravenous injection of human umbilical cord blood cells on the levels of N-acetylaspartate, creatine and phosphocreatine, choline-containing compounds, glutamine and glutamate, and myoinositol in morphologically intact areas of the cortex, white matter, and hippocampus of children with consequences of traumatic brain injury was studied by single voxel 1H magnetic resonance spectroscopy. It was shown that cell therapy increases the content of N-acetylaspartate, a marker of functional integrity of neurons, in the white matter and in the cortex at the boundary between the frontotemporal and parietal lobes and reduces neurological deficit

Characteristics of Diffusion in the Corticospinal Tract of Patients with Early Stage of Schizophrenia: Diffusion Tensor Magnetic Resonance Imaging

Specific features of diffusion in the cerebral corticospinal tract of patients with early stages of schizophrenia were studied using methods of diffusion tensor magnetic-resonance imaging and magnetic resonance spectroscopy. A decrease in the coefficient of fractional anisotropy in the posterior limb of the internal capsule and an increase in diffusion coefficient in the radiate crown and motor cortex were observed. The results reflect different mechanisms of changes in water diffusion in various areas of the corticospinal tract: changes in nerve fiber microstructure in the internal capsule of the left hemisphere and a decrease in their density in the motor cortex and radiate crown.

Diffusion in the Corpus Callosum in Patients with Early Schizophrenia

Diffusion in the cerebral corpus callosum in patients with early schizophrenia was studied by diffusion tensor MRT and magnetic resonance spectroscopy. The fraction anisotropy coefficient in the corpus callosum knee was low as a result of high radial diffusion. Spectroscopy detected a decrease of N-acetylaspartate level in the corpus callosum knee indicating axonal lesion during the early stage of schizophrenia.

Optimization of signal-to-noise ratio in the in vivo31P magnetic resonance spectra of the human brain

The main problem in 31P magnetic resonance spectroscopy is a low signal-to-noise ratio (SNR) of spectra acquired with clinical magnetic resonance imaging (MRI) scanners. Using spin-spin phosphorus-proton (31P-1H) decoupling and heteronuclear Overhauser effect and taking into account the effect of the longitudinal relaxation time T1 on the SNR, the method for localization and excitation of the region of interest (Image Selected in vivo Spectroscopy pulse sequence) was optimized to increase the SNR in the 31P magnetic resonance spectra of the human brain to ~50% without increasing signal acquisition time.

Cerebral quantification of N-acetyl aspartate, aspartate, and glutamate levels in local structures of the human brain using J-editing of 1H magnetic resonance spectra in vivo

A procedure was developed for the first time for simultaneous in vivo quantification of local aspartate and glutamate concentrations in the human brain using 1H magnetic resonance spectroscopy (1H MRS) and spectral J-editing. The MEGA-PRESS pulse sequence was modified to observe β-CH2 nonequivalent proton resonances of aspartate (δ 2.65 and 2.80) and glutamate (δ 2.04 and 2.12) overlapped by signals of other metabolites. The frequencies, frequency selective pulse durations, and optimal echo times were selected by simulation and experimentally (for phantoms and in the brain in vivo).

An Increase in Cerebral γ-Amino Butyric Acid Concentration in Children with Mild Traumatic Brain Injury in the Acute Phase: 1 H MRS Study

In this study, the concentrations of major inhibitory (γ-amino butyric acid) and excitatory (glutamate) neurotransmitters have been estimated for the first time in the norman appearing brain tissue in children with mild traumatic brain injury using magnetic resonance and computer tomography data. 1H magnetic resonance spectra were processed with the J-difference editing technique. It was shown that after mild traumatic brain injury, the concentration of γ-amino butyric acid increases (by 36%) in the frontal lobes, that shifts the inhibitory/excitatory (γ-amino butyric acid/glutamate) balance. It is found that using standart MEGA-PRESS pulse sequence for γ-amino butyric concentration quantification leads to masking the effect of γ-amino butyric acid alteration because the collected signal consists of the signals produced from protons of γ-methylene group of the γ-amino butyric acid and signals from protons of mobile amino-acid chains of proteins. Therefore, a pulse sequence should be modified with symmetrical suppression of signals from mobile amino-acid chains of proteins.