Effect of Carr-Purcell refocusing pulse trains on transverse relaxation times of metabolites in rat brain at 9.4 Tesla

Dinesh Kumar Deelchand; Pierre Gilles Henry; Małgorzata Marjańska

doi:10.1002/mrm.25088

Effect of Carr-Purcell refocusing pulse trains on transverse relaxation times of metabolites in rat brain at 9.4 Tesla

Dinesh Kumar Deelchand, Pierre Gilles Henry, Małgorzata Marjańska

Center for Magnetic Resonance Research

Research output: Contribution to journal › Article › peer-review

20 Scopus citations

Abstract

Purpose: To investigate the effect of Carr-Purcell (CP) pulse trains on transverse relaxation times, T₂, of tissue water and metabolites (both noncoupled and J-coupled spins) in the rat brain at 9.4 Tesla (T) using LASER, CP-LASER, and T_2ρ-LASER sequences.

Methods: Proton NMR spectra were measured in rat brain in vivo at 9.4T. Spectra were acquired at multiple echo times ranging from 18 to 402 ms. All spectra were analyzed using LCModel with simulated basis sets. Signals of metabolites as a function of echo time were fitted using a mono-exponential function to determine their T₂ relaxation times.

Results: Measured T₂s for tissue water and all metabolites were significantly longer with CP-LASER and T_2ρ-LASER compared with LASER. The T₂ increased by a factor of ∼1.3 for noncoupled and weakly coupled spins (e.g., N-Acetylaspartate and total creatine) and by a factor of ∼2 (e.g., glutamine and taurine) to ∼4 (e.g., glutamate and myo-inositol) for strongly coupled spins.

Conclusion: Application of a CP pulse train results in a larger increase in T₂ relaxation times for strongly coupled spins than for noncoupled (singlet) and weakly coupled spins. This needs to be taken into account when correcting for T₂ relaxation in CP-like sequences such as LASER.

Original language	English (US)
Pages (from-to)	13-20
Number of pages	8
Journal	Magnetic resonance in medicine
Volume	73
Issue number	1
DOIs	https://doi.org/10.1002/mrm.25088
State	Published - Jan 1 2015

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Publisher Copyright:
© 2014 Wiley Periodicals, Inc.

Keywords

Brain
CP pulse train
LASER
LCModel
T

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Effect of Carr-Purcell refocusing pulse trains on transverse relaxation times of metabolites in rat brain at 9.4 Tesla

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