Metabolite-cycled STEAM and semi-LASER localization for MR spectroscopy of the human brain at 9.4T

Giapitzakis, Ioannis-Angelos; Shao, Tingting; Avdievich, Nikolai; Mekle, Ralf; Kreis, Roland; Henning, Anke (2018). Metabolite-cycled STEAM and semi-LASER localization for MR spectroscopy of the human brain at 9.4T. Magnetic resonance in medicine, 79(4), pp. 1841-1850. Wiley-Liss 10.1002/mrm.26873

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Metabolite cycling (MC) is an MRS technique for the simultaneous acquisition of water and metabolite spectra that avoids chemical exchange saturation transfer effects and for which water may serve as a reference signal or contain additional information in functional or diffusion studies. Here, MC was developed for human investigations at ultrahigh field.

MC-STEAM and MC-semi-LASER are introduced at 9.4T with an optimized inversion pulse and elaborate coil setup. Experimental and simulation results are given for the implementation of adiabatic inversion pulses for MC. The two techniques are compared, and the effect of frequency and phase correction based on the MC water spectra is evaluated. Finally, absolute quantification of metabolites is performed.

The proposed coil configuration results in a maximum B1 + of 48 μΤ in a voxel within the occipital lobe. Frequency and phase correction of single acquisitions improve signal-to-noise ratio (SNR) and linewidth, leading to high-resolution spectra. The improvement of SNR of N-acetylaspartate (SNRNAA ) for frequency aligned data, acquired with MC-STEAM and MC-semi-LASER, are 37% and 30%, respectively (P < 0.05). Moreover, a doubling of the SNRNAA for MC-semi-LASER in comparison with MC-STEAM is observed (P < 0.05). Concentration levels for 18 metabolites from the human occipital lobe are reported, as acquired with both MC-STEAM and MC-semi-LASER.

This work introduces a novel methodology for single-voxel MRS on a 9.4T whole-body scanner and highlights the advantages of semi-LASER compared to STEAM in terms of excitation profile. In comparison with MC-STEAM, MC-semi-LASER yields spectra with higher SNR. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic, Interventional and Paediatric Radiology > DCR Magnetic Resonance Spectroscopy and Methodology (AMSM)
04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR)
04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Forschungsbereich Pavillon 52 > Abt. Magnetresonanz-Spektroskopie und Methodologie, AMSM

UniBE Contributor:

Kreis, Roland


600 Technology > 610 Medicine & health








Roland Kreis

Date Deposited:

06 Mar 2018 10:52

Last Modified:

13 Mar 2020 14:12

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