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Abstract #2014

Editing Magnetic Resonance Spectroscopy of Lactate at High Fields: Improved Efficiency by Inclusion of FOCI Pulses and Elimination of Co-Edited Macromolecules

Jannie P. Wijnen1, Catalina S. Arteaga de Castro1, Vincent Oltman Boer2, Anna Andreychenko1, Peter R. Luijten1, Bas Neggers3, Dennis W.J. Klomp1

1Radiology, University Medical Centre Utrecht, Utrecht, Netherlands; 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 3Psychiatry, University Medical Centre Utrecht, Utrecht, Netherlands

The weakly coupled spin system of low concentrated lactate can be measured with MRS editing techniques. Obtaining this at the potentially high sensitivity of high field strength can be challenging due to the low available B1+ field resulting in narrow bandwidth refocusing pulses and therefore in large chemical shift displacement errors (CSDE). Frequency offset corrected inversion (FOCI) pulses substantially increase the bandwidth of adiabatic pulses and are used in this study in a MEGA-sLASER editing sequence for highly efficient measurements of lactate. Combined with nulling of co-edited macromolecules, we demonstrate that artefact free lactate signals can be detected in the human brain at 7T.

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Keywords

accurate acquisition acquisitions adiabatic aligned already approximately around artifact available bandwidth black boosted brain broadband chemical choline coedited combined concentration considered considering contaminate corrected correction cost coupled coupling dark detectable detection dispersion displacement edited editing efficiency efficient elimination errors establish even excludes excluding feasible field fields free frequency gain generated good gray healthy human hyperbolic importantly improved in vivo inclusion indicator influence inherent intensities inversion investigate lactate macromolecular macromolecule macromolecules measure measured medical mega metabolic metabolite modulation narrow notice nulled nulling offset original overlap particular peak performance peter position processes profile profiles psychiatry pulse pulses questionable radiology reduced refocusing respectively scanner secant severely shapes since singlet spatial spectra spectroscopy spectrum spin spins stability still strength strengths substantial substantially sufficient suggested system systems various volume volunteers weakly