•
– Choline (Cho)
Glutamine (Gln)
1010In vivo NMR spectroscopy : principle and techniques, R.A. de Graff. 2nd
ed. 2007
? (Glu Gln)? (Glu, Gln)
11 Hz PPM
•
MEGA PRESS for GABAMEGA PRESS for GABA
• Spectral editing scheme for detection of in vivo GABA in PNAS
1993 by Rothman DL.
• Implement in PRESS sequence in NMR Bio 1998 by M Mescher and M
Garwood (MEGA PRESS)
Edit on Partial saturated
by M. Mescher and M. Garwood (MEGA-PRESS)Pulse 30x30x30 mm3, 256
measurements
Edit on – Edit off
1H1H
• (mM) ~ (SNR) • (1 ~ 4 ppm) ~ (1 4 ppm)
S Q• MRS Quality – (SNR) (FWHM)( ) ( ) – voxel size
(shimming)– (shimming)
– TR = 2.0 sec ~ 4
• Voxel size : 20x20x20 mm3~ 8 ml. fMRI 4 4 5 3 0 08 l– fMRI :
4x4x5 mm3 ~ 0.08 ml.
•
Average:64 SNR:33
(shimming)
• •
•
–SNR
1919
3T vs 7T MRS3T vs 7T MRS
2020In vivo NMR spectroscopy : principle and techniques, R.A. de Graff. 2nd
ed. 2007
MRSMRS
–
2121
MRSMRS
•
•
M ( l/l)– mM (mmol/l) – : (Cre)
2222
MRS:MRS:
• Localized MRS in hippocampus by 15x20x10 pp p y mm3 box
• Reduced Glx in IBS patients G• Glx has negative correlation with
state anxiety
AJG 2010, D. Niddam et. al.
•
– fMRI MRS – Focus on neurotransmitters such as GluGABA
• Functional MRS (fMRS) – Dynamic metabolic change during stimuli –
MRS with brain activity (BOLDEEGMEG)MRS with brain activity (BOLD
EEG MEG) – MRS with resting state fMRI
26
•
• –
Visual fMRS experimentVisual fMRS experiment
JCBFM2007 S M i t l• JCBFM2007, S. Mangia
et. al.
•
Localized MRS in visual cortex by 20x22x20
mm3 box at 7T
•
Block design with 5.3 min. visual stimuli
• Glu and Lac increase with stimulusGlu
and Lac increase with stimulus • Glc
and Asp decrease with stimulus ???
28
Motor fMRS experimentMotor fMRS experiment
• NeuroImage2014, B. Schaller et. al.
•
Localized MRS covering motor and somatosensory
3area by 17x20x17 mm3 box at 7T
•
Block design with 5 min. finger tapping in both hand
• Glu and Lac increase with stimulus
29
•
EEG or MEG activity– EEG or MEG activity •
– Glu GABA ? – Glu GABA ?Glu GABA ?
30
MRS and brain activityMRS and brain activity
• Resting state GABA level in visual cortex predicted the HRF, EEG
and MEG activity during visual stimuli
• PNAS2009, S. Muthukumaraswamya et. al • J Neurosci2009 R Edden et
al• J Neurosci2009, R. Edden et. al • HBM2012, S. Muthukumaraswamya
et. al
31
MRS and brain activityMRS and brain activity
• Resting state Glu level in dorsal anterior cingulate cortex
(dACC) predicted the individual BOLD response to auditory cognitive
control task (PNAS2012 Lauditory cognitive control task (PNAS2012,
L. Falkenberg et. al.)
• Resting state Gaba and Glu level in ventromedial prefrontal
cortex (vmPFC) predicted the individual p e o a co e ( C) p ed c ed
e d dua behavioral performance in reward guided decision making
task (Nat Neurosci2012, G. Jocham et. al.)
32
MRS and resting state
fMRIMRS and resting state fMRI
• Resting state Glu and GABA level in posterior medial cortex (PMC)
predict the individual functional connectivity of default mode
network (Neuroimage2013connectivity of default mode network
(Neuroimage2013, D. Kapogiannis et. al.)
• Resting state Glu level in medial prefrontal cortex (mPFC) di h i
di id l f i l i i fpredict the individual functional connectivity
of a
subcortical network (PLOSOne2013, NW. Duncan et. al.)
33
Magnetic Resonance Spectroscopic Imaging
(MRSI)
• Combine MRS and MRI to acquire metabolite information from whole
slice – Metabolite maps – Cover multiple regions of interest
• Limitation in traditional MRSILimitation in traditional MRSI –
Limited spatial coverage – Long acquisition timeLong acquisition
time – Low spatial resolution
34
fast MRSI technique: (P t ) E h Pl
Five metabolite maps in 8 minutes (PEPSI) versus 1 hour
(traditional MRSI)
(Proton) Echo Planar Spectroscopic Imaging “(P)EPSI”
• Combine EPI and MRS to reduce scan time proposed by Dr. P.
Mansfield in 1984
• Automatic analysis tool for absolute metabolite y concentrations
(Neuroimage 2012; J Neuroimaging 13)
PEPSI in sagittal and transverse plane
35
Application : metabolites along medial wall • Patients with pain
syndrome : Myofascial pain syndrome• Patients with pain syndrome :
Myofascial pain syndrome,
Irritable bowel syndrome, headache etc.. • Develop voxel based
analysis (VBM) method for group
l i i MRSIanalysis in MRSI
• Normalized metabolites maps from 24 subjects using
statisticalNormalized metabolites maps from 24 subjects using
statistical nonparametric mapping algorithm
• Age effect (>31 yrs.
and < 31 yrs.) in right and left dorsal anterior cingulate, left
posterior cingulate
• Hemispheric asymmetry in mid
tCr
36
3D PEPSI for whole brain coverage Technique and Automatic analysis
tool developed by research group of• Technique and Automatic
analysis tool developed by research group of A. A. Maudsley
(NMRBio2006; MRM2009; NMRBio2009; MRM2010; NMRBio2011;
MRM2014)
• 26 minutes for 18 slices, spatial resolution around 5.6x5.6x10
mm3
37