Author Of 4 Presentations
NEUROTRANSMISSION DISTURBANCES AFTER MILD PEDIATRIC TBI
Abstract
Background
The vast majority of mild traumatic brain injury (mTBI) cases do not lead to abnormalities of brain structures. The correlation between early structural neuroimaging findings and long-term clinical outcomes is weak.
Objectives
The main aim of this work was to estimate changes in in vivo cerebral GABA and Glutamate concentrations after acute mTBI using 1H MRS.
Methods
Two groups of participants were included in the study: patients (n=11, mean age–16±2 years) with acute mTBI (mean time between trauma and MRI examination 40±20 hours); 8 healthy children (mean age-16±1 years) without history of any TBIs. MR acquisition: 1H MR spectra were acquired on scanner 3 T MRI scaner using PRESS (NAA, Creatine, Choline signals) and MEGA PRESS (GABA and Glutamate signals) pulse sequences. All voxels in size of 25×25×30 mm were located in the frontal lobe
Results
The main effect on the [GABA] was found (Z=2.03, p<0.05), with the patients having higher [GABA] as compared to the control group (36%). Absolute concentrations of NAA+NAAG, tCho, tCr and glutamate were unchanged.
Conclusion
This study for the first time revealed increased cerebral [GABA] as well as disorders in the [GABA]/[GLX] balance in the pediatric acute mTBI. The most likely cause of [GABA] increase is growth of free pool of GABA (non-related to GABA receptors). Postconcussion changes of neurotransmitter revealed in the present study could be promising for understanding of functional consequences of MRI negative TBI.
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DISRUPTION IN THE NORMAL FUNCTIONING OF THE MALATE-ASPARTATE SHUTTLE AFTER SEVERE PEDIATRIC TBI
Abstract
Background
Previous 1H-MRS studies reported significant decrease of major neuronal marker (N-acetylaspartate (NAA)) concentration after severe TBI, The possible reasons of NAA reduction is not still completely known. Disruption of the NAA synthesis from aspartate Asp may result to its decrease.
Objectives
The main idea of this study is investigation of dynamic changes in NAA, Asp and glutamate (Glu) concentrations using proton magnetic resonance spectroscopy.
Methods
We studied 2 patients groups: Eight children (mean age-14±2 years) with acute sTBI (23±4 hours after trauma) and seven patients with chronic sTBI (3 months after trauma). were Control group consisted of 11 healthy children (mean age-15±1 years) without history of any TBI. AspMEGA PRESS were acquired from voxels located in the frontal lobe (fig.1).
Results
NAA and Asp concentrations are reduced in the both patient groups (acute sTBI - on 65% and 61%, chronic sTBI – on 65% and 61%). Glu is significantly reduced only in acute sTBI, however, a significant decrease in the Asp/Glu ratio was found in patients with chronic sTBI.
Conclusion
Since stoichiometric Asp-Glu ratio is maintained by the exchange of glutamate with mitochondrial aspartate, significant reduction of [Asp]/[Glu] may indicates a disruption in the normal functioning of the malate-aspartate shuttle in chronic sTBI. Reduced Glu and Asp concentrations in acute sTBI are associated with excitotoxicity.
This work was supported by RFBR grant 17-04-01149.
LENTICULOSTRIATE ARTERIES PATHOLOGY IN CHILDREN WITH BASAL GANGLIA STROKE FOLLOWING MINOR HEAD INJURIES.
Abstract
Background
Minor head injuries usually cause no severe complications. The impact on the skull causes an opposite movement of the brain parenchyma, with stretching of the vessels because of the high moment of inertia. This leads to a traumatic endothelial intimal lesion, followed by fibrin accumulation and the formation of a white thrombus occluding the lumen [1].
Objectives
To detect lenticulostriate arteries pathology in children with basal ganglia stroke.
To compare sensitivity and specificity of MRI ant MDCT in identifying ischemic lesions.
Methods
CT and MRI of 31 pediatric patients with acute basal ganglia stroke were retrospectively evaluated. All patients had hemiparesis and underwent a comprehensive examination including CT, MRI and MRA. The control group consisted of 15 children without diagnostic findings. Student's t-test was used.
Results
Ischemic lesions were visualized in 31 patients using MRI and in 18 patient using CT. MRI sensitivity and specificity were 100% and 100%. CT sensitivity and specificity were 58% and 94%. Linear areas of hyperdensity in region of lenticulostriate arteries passage were detected in 22 patients and in 1 control group child. A statistically significant difference (p<0,05) was observed between measurements of mean density in group of patients (62,9±6,55 (p<0,5)) and control group (34,6±6,1 (p<0,5).
Conclusion
Linear areas of hyperdensity in region of lenticulostriate arteries passage in patients with acute basal ganglia stroke were regarded as blood clots that can play a major role in pathogenesis of basal ganglia stroke. MRI sensitivity in identifying ischemic lesions is twice as large as MDCT.
HYPERBARIC OXYGENATION ACTIVATES CEREBRAL METABOLISM AND FUNCTIONAL CONNECTIVITY
Abstract
Background
Hyperbaric oxygenation (HBO) has proved itself as an effective way of treatment in different cases, for example in hypoxia. However, the exact in vivo biochemical mechanisms of HBO are to be revealed.
Objectives
We used 31P and 1H magnetic resonance spectroscopy (MRS), as well as resting state functional magnetic resonance imaging (rs-fMRI) in order to find the effects of one HBO session on human brain in vivo.
Methods
MRI scanner 3.0T and hyperbaric chamber Sechrist 3200 were used in the study. Seventeen subjects participated in 31P MRS part, and 12 subjects - in 1H and rs-fMRI part. The data were collected in MRI scanner during ~20 minutes before HBO session and right after it. Spectroscopy data were processed in jMRUI (in case of 31P) and LCModel (1H). The concentrations of creatine phosphate (PCr), ATP and NAD (indirectrly) in whole brain, and of N-acetylaspartate (NAA) in voxels, (see fig.1) after HBO were normalized on the corresponding values after HBO, these values were compared with the value=1 (Mann-Whitney). Rs-fMRI data were processed in CONN (Matlab), the effect of HBO on MPFC-PCC connectivity was found.
Results
After HBO session decreased: PCr (by 3%), NAA in MPFC and PCC (by 4%), NAD increased (by 6%), ATP remained unchanged. The MPFC-PCC connectivity increased (fig.2)
Conclusion
Decrease in PCr and NAA manifestates energy metabolism activation. Together with the increase in NAD and functional connectivity this is the confirmation of HBO effectiveness even at low pressures, that may help to overcome the effect of such diseases as acute ischemia or TBI.