fMRI and MRS measures of neuroplasticity in the pharyngeal motor cortex

Michou, Emilia; Williams, S. R.; Vidyasagar, Rishma; Downey, Darragh; Mistry, Satish; Edden, Richard A.E.; Hamdy, Shaheen

doi:10.1016/j.neuroimage.2015.05.007

Cited by 22 publications

(14 citation statements)

References 80 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Head motion and susceptibility distortion by movement interaction was corrected using the Realign and Unwarp method (Andersson et al, 2001). Additionally, the ArtRepair Toolbox (Mazaika et al, 2009) was used to correct any data sets which showed movement greater than 2 mm as reported by Michou et al (2015). Four patient and five control data sets required repairing.…”

Section: Methodsmentioning

confidence: 99%

Brain imaging correlates of recovered swallowing after dysphagic stroke: A fMRI and DWI study

Mihai

Otto

Domín

et al. 2016

NeuroImage: Clinical

Self Cite

View full text Add to dashboard Cite

Neurogenic dysphagia frequently occurs after stroke and deglutitive aspiration is one of the main reasons for subacute death after stroke. Although promising therapeutic interventions for neurogenic dysphagia are being developed, the functional neuroanatomy of recovered swallowing in this population remains uncertain. Here, we investigated 18 patients post-stroke who recovered from dysphagia using an event related functional magnetic resonance imaging (fMRI) study of swallowing. Patients were characterized by initial dysphagia score (mild to severe), lesion mapping, white matter fractional anisotropy (FA) of the pyramidal tracts, and swallowing performance measurement during fMRI scanning. Eighteen age matched healthy participants served as a control group. Overall, patients showed decreased fMRI-activation in the entire swallowing network apart from an increase of activation in the contralesional primary somatosensory cortex (S1). Moreover, fMRI activation in contralesional S1 correlated with initial dysphagia score. Finally, when lesions of the pyramidal tract were more severe, recovered swallowing appeared to be associated with asymmetric activation of the ipsilesional anterior cerebellum. Taken together, our data support a role for increased contralesional somatosensory resources and ipsilesional anterior cerebellum feed forward loops for recovered swallowing after dysphagia following stroke.

show abstract

Section: Methodsmentioning

confidence: 99%

Brain imaging correlates of recovered swallowing after dysphagic stroke: A fMRI and DWI study

Mihai

Otto

Domín

et al. 2016

NeuroImage: Clinical

Self Cite

View full text Add to dashboard Cite

show abstract

“…One of the key inhibitory metabolites is γ‐aminobutyric acid (GABA), which is the main inhibitory neurotransmitter of the brain and is believed to have a direct impact on BOLD contrast through regulation of neuronal firing rates 6, 7, 8. In the human brain in vivo , the relationship between GABA and BOLD signals has been investigated in studies that combined fMRI and MRS 7, 9, 10, 11, 12, 13, 14, 15…”

Section: Introductionmentioning

confidence: 99%

Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T

et al. 2018

View full text Add to dashboard Cite

The combination of functional MRI (fMRI) and MRS is a promising approach to relate BOLD imaging to neuronal metabolism, especially at high field strength. However, typical scan times for GABA edited spectroscopy are of the order of 6‐30 min, which is long compared with functional changes observed with fMRI.The aim of this study is to reduce scan time and increase GABA sensitivity for edited spectroscopy in the human visual cortex, by enlarging the volume of activated tissue in the primary visual cortex. A dedicated setup at 7 T for combined fMRI and GABA MRS is developed. This setup consists of a half volume multi‐transmit coil with a large screen for visual cortex activation, two high density receive arrays and an optimized single‐voxel MEGA‐sLASER sequence with macromolecular suppression for signal acquisition.The coil setup performance as well as the GABA measurement speed, SNR, and stability were evaluated. A 2.2‐fold gain of the average SNR for GABA detection was obtained, as compared with a conventional 7 T setup. This was achieved by increasing the viewing angle of the participant with respect to the visual stimulus, thereby activating almost the entire primary visual cortex, allowing larger spectroscopy measurement volumes and resulting in an improved GABA SNR. Fewer than 16 signal averages, lasting 1 min 23 s in total, were needed for the GABA fit method to become stable, as demonstrated in three participants. The stability of the measurement setup was sufficient to detect GABA with an accuracy of 5%, as determined with a GABA phantom. In vivo, larger variations in GABA concentration are found: 14‐25%. Overall, the results bring functional GABA detections at a temporal resolution closer to the physiological time scale of BOLD cortex activation.

show abstract

“…The chemical and structural similarities of Glu, Gln and GABA result in similar magnetic resonance (MR) spectra, making their separation in vivo challenging at 3 T. Glu and Gln have been measured at 3 T using different methods, such as TE‐averaged point‐resolved spectroscopy (PRESS), short‐echo stimulated echo acquisition mode (STEAM) (TE = 6.5 ms), PRESS and proton echo planar spectroscopic imaging (PEPSI) . GABA, however, has mostly been detected using J ‐difference‐edited Mescher–Garwood point‐resolved spectroscopy (MEGA‐PRESS), which has developed into a robust and reliable method for the quantification of GABA . J ‐difference editing is based on the quantification of the visually detectable GABA protons resonating around 3.01 ppm.…”

Section: Introductionmentioning

confidence: 99%

“…12 GABA, however, has mostly been detected using J-difference-edited Mescher-Garwood point-resolved spectroscopy (MEGA-PRESS), 13 which has developed into a robust and reliable method for the quantification of GABA. [14][15][16][17][18] J-difference editing is based on the quantification of the visually detectable GABA protons resonating around 3.01 ppm. The GABA C3 multiplet which is manipulated for editing resonates at 1.89 ppm close to the Glu and Gln C3 multiplets.…”

mentioning

confidence: 99%

Quantification of GABA, glutamate and glutamine in a single measurement at 3 T using GABA‐edited MEGA‐PRESS

et al. 2017

Self Cite

View full text Add to dashboard Cite

γ‐Aminobutyric acid (GABA) and glutamate (Glu), major neurotransmitters in the brain, are recycled through glutamine (Gln). All three metabolites can be measured by magnetic resonance spectroscopy in vivo, although GABA measurement at 3 T requires an extra editing acquisition, such as Mescher–Garwood point‐resolved spectroscopy (MEGA‐PRESS). In a GABA‐edited MEGA‐PRESS spectrum, Glu and Gln co‐edit with GABA, providing the possibility to measure all three in one acquisition. In this study, we investigated the reliability of the composite Glu + Gln (Glx) peak estimation and the possibility of Glu and Gln separation in GABA‐edited MEGA‐PRESS spectra. The data acquired in vivo were used to develop a quality assessment framework which identified MEGA‐PRESS spectra in which Glu and Gln could be estimated reliably. Phantoms containing Glu, Gln, GABA and N‐acetylaspartate (NAA) at different concentrations were scanned using GABA‐edited MEGA‐PRESS at 3 T. Fifty‐six sets of spectra in five brain regions were acquired from 36 healthy volunteers. Based on the Glu/Gln ratio, data were classified as either within or outside the physiological range. A peak‐by‐peak quality assessment was performed on all data to investigate whether quality metrics can discriminate between these two classes of spectra. The quality metrics were as follows: the GABA signal‐to‐noise ratio, the NAA linewidth and the Glx Cramer–Rao lower bound (CRLB). The Glu and Gln concentrations were estimated with precision across all phantoms with a linear relationship between the measured and true concentrations: R 1 = 0.95 for Glu and R 1 = 0.91 for Gln. A quality assessment framework was set based on the criteria necessary for a good GABA‐edited MEGA‐PRESS spectrum. Simultaneous criteria of NAA linewidth <8 Hz and Glx CRLB <16% were defined as optimum features for reliable Glu and Gln quantification. Glu and Gln can be reliably quantified from GABA‐edited MEGA‐PRESS acquisitions. However, this reliability should be controlled using the quality assessment methods suggested in this work.

show abstract

fMRI and MRS measures of neuroplasticity in the pharyngeal motor cortex

Cited by 22 publications

References 80 publications

Brain imaging correlates of recovered swallowing after dysphagic stroke: A fMRI and DWI study

Brain imaging correlates of recovered swallowing after dysphagic stroke: A fMRI and DWI study

Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T

Quantification of GABA, glutamate and glutamine in a single measurement at 3 T using GABA‐edited MEGA‐PRESS

Contact Info

Product

Resources

About