A major problem in quantification of proton metabolites obtained by high field magnetic resonance (MR) spectroscopic imaging (MRSI) at short TE is separating the metabolite resonances from the uneven and varying baseline Some of the baseline fluctuations are due to out-of-volume water and lipid signals, while other variations are due to the presence of macromolecules We propose a series of measures to improve the ability to separate metabolite and baseline signals, the most important of which involves obtaining a series of moderate signal-to noise (S/N) spectra at differing TE times with a sequence that includes closely spaced 180 degrees pulses (CP pulse train) to reduce J evolution for strongly coupled spins prior to acquisition This preserves the spectral patterns for strongly coupled resonances at the different TE values even though the signal amplitudes decay due to T2 relaxation Simultaneous fitting of the suite of spectra is expected to enable improved separation of metabolite signals from baseline, and to provide more reliable estimates of metabolite resonance areas A number of additional measures including 1) improved RF pulses, including improvement of hyperbolic secant pulses and a spin echo pulse cascade with immunity to B1 inhomogenicity for the CP pulse train, 2) improved methods of shimming, 3) improved MRSI acquisition sequences, 4) improved methods for processing of metabolite spectra, and 5) improvements for metabolite quantification in institutional units, based on coanalysis with tissue segmented structural MRI data, are planned Finally, a metabolite atlas of normal brain, reflecting regional metabolite levels and variations, will be developed This proposal is coordinated with the partner IRPG proposal for sharing of programs, pulses, data, and information to enhance the research at both sites.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
5R01EB000766-04
Application #
6913547
Study Section
Special Emphasis Panel (ZRG1-SSS-X (30))
Program Officer
Mclaughlin, Alan Charles
Project Start
2002-09-30
Project End
2007-06-30
Budget Start
2005-07-01
Budget End
2006-06-30
Support Year
4
Fiscal Year
2005
Total Cost
$371,250
Indirect Cost
Name
Northern California Institute Research & Education
Department
Type
DUNS #
613338789
City
San Francisco
State
CA
Country
United States
Zip Code
94121
Liu, Hui; Matson, Gerald B (2011) Radiofrequency pulse designs for three-dimensional MRI providing uniform tipping in inhomogeneous B? fields. Magn Reson Med 66:1254-66
Kaiser, Lana G; Marjanska, Malgorzata; Matson, Gerald B et al. (2010) (1)H MRS detection of glycine residue of reduced glutathione in vivo. J Magn Reson 202:259-66
Matson, Gerald B; Young, Karl; Kaiser, Lana G (2009) RF pulses for in vivo spectroscopy at high field designed under conditions of limited power using optimal control. J Magn Reson 199:30-40
Young, Karl; Schuff, Norbert (2008) Measuring structural complexity in brain images. Neuroimage 39:1721-30
Kaiser, Lana G; Young, Karl; Matson, Gerald B (2008) Numerical simulations of localized high field 1H MR spectroscopy. J Magn Reson 195:67-75
Zhu, Xiaoping; Ebel, Andreas; Ji, Jim X et al. (2007) Spectral phase-corrected GRAPPA reconstruction of three-dimensional echo-planar spectroscopic imaging (3D-EPSI). Magn Reson Med 57:815-20
Zhu, Xiaoping; Schuff, Norbert; Kornak, John et al. (2006) Effects of Alzheimer disease on fronto-parietal brain N-acetyl aspartate and myo-inositol using magnetic resonance spectroscopic imaging. Alzheimer Dis Assoc Disord 20:77-85
Zhu, X P; Young, K; Ebel, A et al. (2006) Robust analysis of short echo time (1)H MRSI of human brain. Magn Reson Med 55:706-11
Soher, Brian J; Pattany, Pradip M; Matson, Gerald B et al. (2005) Observation of coupled 1H metabolite resonances at long TE. Magn Reson Med 53:1283-7
Young, Karl; Chen, Yue; Kornak, John et al. (2005) Summarizing complexity in high dimensions. Phys Rev Lett 94:098701

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