Magnetic resonance (MR) spectroscopic measurement of γ-aminobutyric acid (GABA) in major depression before and after electroconvulsive therapy

2018 ◽  
Vol 31 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Marie Krøll Knudsen ◽  
Jamie Near ◽  
Anne Bastholm Blicher ◽  
Poul Videbech ◽  
Jakob Udby Blicher
Keyword(s):  
Prefrontal Cortex ◽  
Major Depression ◽  
Magnetic Resonance ◽  
Electroconvulsive Therapy ◽  
Healthy Subjects ◽  
Occipital Cortex ◽  
Aminobutyric Acid ◽  
Secondary Outcome ◽  
Resonance Spectroscopy ◽  
Significant Difference

AbstractObjectivePrior studies suggest that a dysregulation of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) is involved in the pathophysiology of major depression. We aimed to elucidate changes in cortical GABA content in relation to depression and electroconvulsive therapy (ECT) using magnetic resonance spectroscopy (MRS).MethodsIn total, 11 patients with major depression or depressive episode of bipolar disorder (mean pre-ECT Ham-17 of 26) and 11 healthy subjects were recruited. GABA was quantified using short-TE MRS in prefrontal and occipital cortex. Other neurometabolites such as glutathione (GSH), N-acetylaspartate (NAA) and glutamate (Glu) were secondary outcome measures.ResultsNo significant differences in GABA/Cr levels were observed between patients at baseline and healthy subjects in prefrontal cortex, t(20)=0.089, p=0.93 or occipital cortex t(21)=0.37, p=0.72. All patients improved on Ham-17 (mean post-ECT Ham-17 of 9). No significant difference was found in GABA, Glu, glutamine, choline or GSH between pre- and post-ECT values. However, we observed a significant decrease in NAA levels following ECT t(22)=3.89, p=0.0038, and a significant correlation between the NAA decline and the number of ECT sessions p=0.035.ConclusionsOur study does not support prior studies arguing for GABA as a key factor in the treatment effect of ECT on major depression. The reduction in NAA levels following ECT could be due to neuronal loss or a transient dysfunction in prefrontal cortex. As no long-term follow-up scan was performed, it is unknown whether NAA levels will normalise over time.

scholarly journals Analysis of Mental State of Patients after Drug Addiction and Withdrawal Guided by PETCT Image Based on Optimized Image Fusion Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yaowen Pang ◽  
Xiang Peng
Keyword(s):  
Prefrontal Cortex ◽  
Magnetic Resonance ◽  
Visual Stimulation ◽  
Brain Temperature ◽  
Statistical Significance ◽  
Normal Group ◽  
Resonance Spectroscopy ◽  
Significant Difference ◽  
Before And After ◽  
The Brain

Blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) studies have shown that drug-dependent patients are activated in different addictive brain areas under the stimulation of relevant environmental cues, which in turn leads to craving and relapse. This study uses magnetic resonance spectroscopy to measure brain temperature to explore the brain temperature changes in different addictive brain regions of heroin and methamphetamine addicts in a short-term withdrawal state and to explore whether the quantitative index of brain temperature change can be used as a diagnostic drug Methods. The subjects were scanned by resting-state MRI spectroscopy first and then subjected to MRI spectroscopy scanning under visual stimulation. The subjects were required to watch the heroin/meth-related clue pictures carefully during visual stimulation. The measured chemical shift value of N-acetyl-aspartic acid (NAA) is substituted into the brain temperature calculation formula T = 37 + 100 to obtain the brain temperature before and after visual stimulation. In addition, the anxiety and depression states of heroin and methamphetamine-dependent patients were evaluated. Results. There was no statistically significant change in the brain temperature of the prefrontal cortex before and after visual stimulation in heroin and methamphetamine-dependent subjects; compared with the normal group, there was no change in prefrontal cortex brain temperature before and after visual stimulation in heroin and methamphetamine-dependent subjects. Statistical Significance. The changes of hippocampal temperature before and after visual stimulation in methamphetamine-dependent patients were not statistically significant; compared with the normal group, there was no statistically significant difference in the changes of hippocampal temperature before and after visual stimulation in methamphetamine-dependent patients. Conclusion. This study initially found that the visual cues related to heroin and methamphetamine were not enough to cause significant changes in the brain temperature of the prefrontal cortex.

scholarly journals Imaging the Pathophysiology of Essential Tremor—A Systematic Review

2021 ◽  
Vol 12 ◽  
Author(s):  
Florian Holtbernd ◽  
N. Jon Shah
Keyword(s):  
Magnetic Resonance ◽  
Essential Tremor ◽  
Neurodegenerative Disorder ◽  
Aminobutyric Acid ◽  
Emission Computed Tomography ◽  
Resonance Spectroscopy ◽  
Gamma Aminobutyric Acid ◽  
Imaging Studies ◽  
Limited Evidence ◽  
Neurotransmitter System

Background: The pathophysiology underlying essential tremor (ET) still is poorly understood. Recent research suggests a pivotal role of the cerebellum in tremor genesis, and an ongoing controversy remains as to whether ET constitutes a neurodegenerative disorder. In addition, mounting evidence indicates that alterations in the gamma-aminobutyric acid neurotransmitter system are involved in ET pathophysiology. Here, we systematically review structural, functional, and metabolic neuroimaging studies and discuss current concepts of ET pathophysiology from an imaging perspective.Methods: We conducted a PubMed and Scopus search from 1966 up to December 2020, entering essential tremor in combination with any of the following search terms and their corresponding abbreviations: positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and gamma-aminobutyric acid (GABA).Results: Altered functional connectivity in the cerebellum and cerebello-thalamico-cortical circuitry is a prevalent finding in functional imaging studies. Reports from structural imaging studies are less consistent, and there is no clear evidence for cerebellar neurodegeneration. However, diffusion tensor imaging robustly points toward microstructural cerebellar changes. Radiotracer imaging suggests that the dopaminergic axis is largely preserved in ET. Similarly, measurements of nigral iron content and neuromelanin are unremarkable in most studies; this is in contrast to Parkinson's disease (PD). PET and MRS studies provide limited evidence for cerebellar and thalamic GABAergic dysfunction.Conclusions: There is robust evidence indicating that the cerebellum plays a key role within a multiple oscillator tremor network which underlies tremor genesis. However, whether cerebellar dysfunction relies on a neurodegenerative process remains unclear. Dopaminergic and iron imaging do not suggest a substantial overlap of ET with PD pathophysiology. There is limited evidence for alterations of the GABAergic neurotransmitter system in ET. The clinical, demographical, and genetic heterogeneity of ET translates into neuroimaging and likely explains the various inconsistencies reported.

scholarly journals Simultaneous Measurement of the BOLD Effect and Metabolic Changes in Response to Visual Stimulation Using the MEGA-PRESS Sequence at 3 T

2021 ◽  
Vol 15 ◽  
Author(s):  
Gerard Eric Dwyer ◽  
Alexander R. Craven ◽  
Justyna Bereśniewicz ◽  
Katarzyna Kazimierczak ◽  
Lars Ersland ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Visual Stimulation ◽  
Occipital Cortex ◽  
Blood Oxygen Level Dependent ◽  
Metabolic Changes ◽  
Water Suppression ◽  
Resonance Spectroscopy ◽  
Indirect Measure ◽  
Bold Effect ◽  
Water Signal

The blood oxygen level dependent (BOLD) effect that provides the contrast in functional magnetic resonance imaging (fMRI) has been demonstrated to affect the linewidth of spectral peaks as measured with magnetic resonance spectroscopy (MRS) and through this, may be used as an indirect measure of cerebral blood flow related to neural activity. By acquiring MR-spectra interleaved with frames without water suppression, it may be possible to image the BOLD effect and associated metabolic changes simultaneously through changes in the linewidth of the unsuppressed water peak. The purpose of this study was to implement this approach with the MEGA-PRESS sequence, widely considered to be the standard sequence for quantitative measurement of GABA at field strengths of 3 T and lower, to observe how changes in both glutamate (measured as Glx) and GABA levels may relate to changes due to the BOLD effect. MR-spectra and fMRI were acquired from the occipital cortex (OCC) of 20 healthy participants whilst undergoing intrascanner visual stimulation in the form of a red and black radial checkerboard, alternating at 8 Hz, in 90 s blocks comprising 30 s of visual stimulation followed by 60 s of rest. Results show very strong agreement between the changes in the linewidth of the unsuppressed water signal and the canonical haemodynamic response function as well as a strong, negative, but not statistically significant, correlation with the Glx signal as measured from the OFF spectra in MEGA-PRESS pairs. Findings from this experiment suggest that the unsuppressed water signal provides a reliable measure of the BOLD effect and that correlations with associated changes in GABA and Glx levels may also be measured. However, discrepancies between metabolite levels as measured from the difference and OFF spectra raise questions regarding the reliability of the respective methods.

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