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If J doesn't evolve, it won't J-resolve: J-PRESS with bandwidth-limited refocusing pulses
Richard A E Edden1, Peter B Barker
1Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, Maryland 21202, USA. raee2@jhu.edu
Magnetic Resonance in Medicine
|May 19, 2011
Summary
The J-PRESS technique in brain spectroscopy can create artifact peaks due to spatially dependent spin evolution. Increasing pulse bandwidth reduces these J-refocused peaks, improving spectral accuracy for metabolites like lactate.
Area of Science:
- Neuroimaging
- Magnetic Resonance Spectroscopy
Background:
- J-PRESS is a 2D J-spectroscopy technique for in vivo human brain studies.
- Accurate resolution of scalar couplings is crucial for spectral analysis.
Purpose of the Study:
- Investigate the impact of spatially dependent spin evolution on J-PRESS spectra at high magnetic fields.
- Characterize artifact peaks in J-PRESS spectra of lactate and N-acetyl aspartate.
Main Methods:
- Utilized PRESS localization within a 2D J-spectroscopy framework.
- Examined the effect of RF pulse bandwidth on spin evolution and spectral appearance.
- Focused on coupled spins in metabolites like lactate and N-acetyl aspartate.
Main Results:
- Spatially dependent evolution of coupling due to limited RF pulse bandwidth creates artifact peaks (J-refocused peaks).
- These J-refocused peaks were observed in J-PRESS spectra of lactate and N-acetyl aspartate.
- Increasing the bandwidth of refocusing pulses significantly reduced the size of these artifact signals.
Conclusions:
- Spatially dependent spin evolution in PRESS localization can lead to artifactual peaks in J-PRESS spectra.
- Optimizing RF pulse bandwidth is critical for accurate J-PRESS spectral interpretation in high-field brain spectroscopy.
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