Document Detail

Selective maximization of (31)P MR spectroscopic signals of in vivo human brain metabolites at 3T.
MedLine Citation:
PMID:  17279535     Owner:  NLM     Status:  MEDLINE    
PURPOSE: To develop a short TR, short TE, large flip angle (LFA), in vivo (31)P MR spectroscopy (MRS) technique at 3T that selectively maximizes the signal-to-noise ratio (SNR) of long T(1) human brain metabolites implicated in bipolar disorder. MATERIALS AND METHODS: Two pulse sequences were evaluated for efficiency. Slice profiles acquired with the scaled, sinc-shaped, radiofrequency (RF) LFA pulses were compared to those acquired with Shinnar-Le Roux (SLR) RF LFA pulses. The SLR-based LFA pulse sequence was used to maximize the inorganic phosphate signal in a phantom, after which volunteer metabolite signals were selectively maximized and compared to their correlates acquired with conventional spin-echo methods. RESULTS: The comparison of slice profiles acquired with sinc-shaped RF LFA pulses vs. SLR RF LFA pulses showed that SLR-based pulse sequences, with their improved excitation and slice profiles, yield significantly better results. In vivo LFA spin-echo MRS implemented with SLR pulses selectively increased the (31)P MRS signal, by as much as 93%, of human brain metabolites that have T(1) times longer than the TR of the acquisition. CONCLUSION: The data show that the LFA technique can be employed in vivo to maximize the signal of long T(1) (31)P brain metabolites at a given TE and TR. LFAs ranging between 120 degrees and 150 degrees are shown to maximize the (31)P signal of human brain metabolites at 3T.
Rose-Ann M Blenman; John D Port; Joel P Felmlee
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Publication Detail:
Type:  Evaluation Studies; Journal Article    
Journal Detail:
Title:  Journal of magnetic resonance imaging : JMRI     Volume:  25     ISSN:  1053-1807     ISO Abbreviation:  J Magn Reson Imaging     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-03-05     Completed Date:  2007-04-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9105850     Medline TA:  J Magn Reson Imaging     Country:  United States    
Other Details:
Languages:  eng     Pagination:  628-34     Citation Subset:  IM    
Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
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MeSH Terms
Brain / metabolism*
Brain Chemistry
Magnetic Resonance Spectroscopy / methods*
Middle Aged
Phantoms, Imaging
Phosphorus Isotopes
Reference Values
Signal Processing, Computer-Assisted*
Time Factors
Reg. No./Substance:
0/Phosphorus Isotopes

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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