TY - JOUR
T1 - Comparison of four 31P single-voxel MRS sequences in the human brain at 9.4 T
AU - Dorst, Johanna
AU - Ruhm, Loreen
AU - Avdievich, Nikolai
AU - Bogner, Wolfgang
AU - Henning, Anke
N1 - Publisher Copyright:
© 2021 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.
PY - 2021/6
Y1 - 2021/6
N2 - Purpose: In this study, different single-voxel localization sequences were implemented and systematically compared for the first time for phosphorous MRS (31P-MRS) in the human brain at 9.4 T. Methods: Two multishot sequences, image-selected in vivo spectroscopy (ISIS) and a conventional slice-selective excitation combined with localization by adiabatic selective refocusing (semiLASER) variant of the spin-echo full intensity–acquired localized spectroscopy (SPECIAL-semiLASER), and two single-shot sequences, semiLASER and stimulated echo acquisition mode (STEAM), were implemented and optimized for 31P-MRS in the human brain at 9.4 T. Pulses and coil setup were optimized, localization accuracy was tested in phantom experiments, and absolute SNR of the sequences was compared in vivo. The SNR per unit time (SNR/t) was derived and compared for all four sequences and verified experimentally for ISIS in two different voxel sizes (3 × 3 × 3 cm3, 5 × 5 × 5 cm3, 10-minute measurement time). Metabolite signals obtained with ISIS were quantified. The possible spectral quality in vivo acquired in clinically feasible time (3:30 minutes, 3 × 3 × 3 cm3) was explored for two different coil setups. Results: All evaluated sequences performed with good localization accuracy in phantom experiments and provided well-resolved spectra in vivo. However, ISIS has the lowest chemical shift displacement error, the best localization accuracy, the highest SNR/t for most metabolites, provides metabolite concentrations comparable to literature values, and is the only one of the sequences that allows for the detection of the whole 31P spectrum, including β–adenosine triphosphate, with the used setup. The SNR/t of STEAM is comparable to the SNR/t of ISIS. The semiLASER and SPECIAL-semiLASER sequences provide good results for metabolites with long T2. Conclusion: At 9.4 T, high-quality single-voxel localized 31P-MRS can be performed in the human brain with different localization methods, each with inherent characteristics suitable for different research issues.
AB - Purpose: In this study, different single-voxel localization sequences were implemented and systematically compared for the first time for phosphorous MRS (31P-MRS) in the human brain at 9.4 T. Methods: Two multishot sequences, image-selected in vivo spectroscopy (ISIS) and a conventional slice-selective excitation combined with localization by adiabatic selective refocusing (semiLASER) variant of the spin-echo full intensity–acquired localized spectroscopy (SPECIAL-semiLASER), and two single-shot sequences, semiLASER and stimulated echo acquisition mode (STEAM), were implemented and optimized for 31P-MRS in the human brain at 9.4 T. Pulses and coil setup were optimized, localization accuracy was tested in phantom experiments, and absolute SNR of the sequences was compared in vivo. The SNR per unit time (SNR/t) was derived and compared for all four sequences and verified experimentally for ISIS in two different voxel sizes (3 × 3 × 3 cm3, 5 × 5 × 5 cm3, 10-minute measurement time). Metabolite signals obtained with ISIS were quantified. The possible spectral quality in vivo acquired in clinically feasible time (3:30 minutes, 3 × 3 × 3 cm3) was explored for two different coil setups. Results: All evaluated sequences performed with good localization accuracy in phantom experiments and provided well-resolved spectra in vivo. However, ISIS has the lowest chemical shift displacement error, the best localization accuracy, the highest SNR/t for most metabolites, provides metabolite concentrations comparable to literature values, and is the only one of the sequences that allows for the detection of the whole 31P spectrum, including β–adenosine triphosphate, with the used setup. The SNR/t of STEAM is comparable to the SNR/t of ISIS. The semiLASER and SPECIAL-semiLASER sequences provide good results for metabolites with long T2. Conclusion: At 9.4 T, high-quality single-voxel localized 31P-MRS can be performed in the human brain with different localization methods, each with inherent characteristics suitable for different research issues.
KW - ISIS
KW - SPECIAL-semiLASER
KW - STEAM
KW - phosphorus
KW - semiLASER
KW - ultrahigh field
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U2 - 10.1002/mrm.28658
DO - 10.1002/mrm.28658
M3 - Article
C2 - 33427322
AN - SCOPUS:85099102902
SN - 0740-3194
VL - 85
SP - 3010
EP - 3026
JO - Magnetic resonance in medicine
JF - Magnetic resonance in medicine
IS - 6
ER -