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Non-water-excitation MR spectroscopy techniques to explore exchanging protons in human brain at 3 T.
Magn Reson Med. 2020 Nov; 84(5):2352-2363.MR

Abstract

PURPOSE

To develop localization sequences for in vivo MR spectroscopy (MRS) on clinical scanners of 3 T to record spectra that are not influenced by magnetization transfer from water.

METHODS

Image-selected in vivo spectroscopy (ISIS) localization and chemical-shift-selective excitation (termed I-CSE) was combined in two ways: first, full ISIS localization plus a frequency-selective spin-echo and second, two-dimensional (2D) ISIS plus a frequency-selective excitation and slice-selective refocusing. The techniques were evaluated at 3 T in phantoms and human subjects in comparison to standard techniques with water presaturation or metabolite-cycling. ISIS included gradient-modulated offset-independent adiabatic (GOIA)-type adiabatic inversion pulses; echo times were 8-10 ms.

RESULTS

The novel 2D and 3D I-CSE methods yield upfield spectra that are comparable to those from standard MRS, except for shorter echo times and a limited frequency range. On the downfield/high-frequency side, they yield much more signal for exchangeable protons when compared to MRS with water presaturation or metabolite-cycling and longer echo times.

CONCLUSION

Novel non-water-excitation MRS sequences offer substantial benefits for the detection of metabolite signals that are otherwise suppressed by saturation transfer from water. Avoiding water saturation and using very short echo times allows direct observation of faster exchanging moieties than was previously possible at 3 T and additionally makes the methods less susceptible to fast T2 relaxation.

Authors+Show Affiliations

Departments of Radiology and Biomedical Research, University of Bern, Bern, Switzerland. Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria.Departments of Radiology and Biomedical Research, University of Bern, Bern, Switzerland.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32602971

Citation

Dziadosz, Martyna, et al. "Non-water-excitation MR Spectroscopy Techniques to Explore Exchanging Protons in Human Brain at 3 T." Magnetic Resonance in Medicine, vol. 84, no. 5, 2020, pp. 2352-2363.
Dziadosz M, Bogner W, Kreis R. Non-water-excitation MR spectroscopy techniques to explore exchanging protons in human brain at 3 T. Magn Reson Med. 2020;84(5):2352-2363.
Dziadosz, M., Bogner, W., & Kreis, R. (2020). Non-water-excitation MR spectroscopy techniques to explore exchanging protons in human brain at 3 T. Magnetic Resonance in Medicine, 84(5), 2352-2363. https://doi.org/10.1002/mrm.28322
Dziadosz M, Bogner W, Kreis R. Non-water-excitation MR Spectroscopy Techniques to Explore Exchanging Protons in Human Brain at 3 T. Magn Reson Med. 2020;84(5):2352-2363. PubMed PMID: 32602971.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Non-water-excitation MR spectroscopy techniques to explore exchanging protons in human brain at 3 T. AU - Dziadosz,Martyna, AU - Bogner,Wolfgang, AU - Kreis,Roland, Y1 - 2020/06/30/ PY - 2020/03/16/received PY - 2020/04/23/revised PY - 2020/04/23/accepted PY - 2020/7/1/pubmed PY - 2020/7/1/medline PY - 2020/7/1/entrez KW - amides KW - brain KW - downfield KW - human KW - magnetization exchange KW - proton MR spectroscopy SP - 2352 EP - 2363 JF - Magnetic resonance in medicine JO - Magn Reson Med VL - 84 IS - 5 N2 - PURPOSE: To develop localization sequences for in vivo MR spectroscopy (MRS) on clinical scanners of 3 T to record spectra that are not influenced by magnetization transfer from water. METHODS: Image-selected in vivo spectroscopy (ISIS) localization and chemical-shift-selective excitation (termed I-CSE) was combined in two ways: first, full ISIS localization plus a frequency-selective spin-echo and second, two-dimensional (2D) ISIS plus a frequency-selective excitation and slice-selective refocusing. The techniques were evaluated at 3 T in phantoms and human subjects in comparison to standard techniques with water presaturation or metabolite-cycling. ISIS included gradient-modulated offset-independent adiabatic (GOIA)-type adiabatic inversion pulses; echo times were 8-10 ms. RESULTS: The novel 2D and 3D I-CSE methods yield upfield spectra that are comparable to those from standard MRS, except for shorter echo times and a limited frequency range. On the downfield/high-frequency side, they yield much more signal for exchangeable protons when compared to MRS with water presaturation or metabolite-cycling and longer echo times. CONCLUSION: Novel non-water-excitation MRS sequences offer substantial benefits for the detection of metabolite signals that are otherwise suppressed by saturation transfer from water. Avoiding water saturation and using very short echo times allows direct observation of faster exchanging moieties than was previously possible at 3 T and additionally makes the methods less susceptible to fast T2 relaxation. SN - 1522-2594 UR - https://www.unboundmedicine.com/medline/citation/32602971/Non-water-excitation_MR_spectroscopy_techniques_to_explore_exchanging_protons_in_human_brain_at_3 T L2 - https://doi.org/10.1002/mrm.28322 DB - PRIME DP - Unbound Medicine ER -
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