Whole-brain quantitative CEST MRI at 7T using parallel transmission methods and B1+ correction

Liebert A, Tkotz K, Herrler J, Linz P, Mennecke A, German A, Liebig P, Gumbrecht R, Schmidt M, Dörfler A, Uder M, Zaiß M, Nagel AM (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Magnetic Resonance in Medicine Wiley

DOI: 10.1002/mrm.28745

Abstract

Purpose: To enable whole-brain quantitative CEST MRI at ultra-high magnetic field strengths (B0 ≥ 7T) within short acquisition times. Methods: Multiple interleaved mode saturation (MIMOSA) was combined with fast online-customized (FOCUS) parallel transmission (pTx) excitation pulses and (Formula presented.) correction to achieve homogenous whole-brain coverage. Examinations of 13 volunteers were performed on a 7T MRI system with 3 different types of pulse sequences: (1) saturation in circular polarized (CP) mode and CP mode readout, (2) MIMOSA and CP readout, and (3) MIMOSA and FOCUS readout. For comparison, the inverse magnetic transfer ratio metric for relayed nuclear Overhauser effect and amide proton transfer were calculated. To investigate the number of required acquisitions for a good (Formula presented.) correction, 4 volunteers were measured with 6 different B1 amplitudes. Finally, time point repeatability was investigated for 6 volunteers. Results: MIMOSA FOCUS sequence using (Formula presented.) correction, with both single and multiple points, reduced inhomogeneity of the CEST contrasts around the occipital lobe and cerebellum. Results indicate that the most stable inter-subject coefficient of variation was achieved using the MIMOSA FOCUS sequence. Time point repeatability of MIMOSA FOCUS with single-point (Formula presented.) correction showed a maximum coefficient of variation below 8% for 3 measurements in a single volunteer. Conclusion: A combination of MIMOSA FOCUS with a single-point (Formula presented.) correction can be used to achieve quantitative CEST measurements at ultra-high magnetic field strengths. Compared to previous (Formula presented.) correction methods, acquisition time can be reduced as additional scans required for (Formula presented.) correction can be omitted.

Authors with CRIS profile

Andrzej Liebert Professur für metabolische und funktionelle MR-Bildgebung Katharina Tkotz Max Schaldach-Stiftungsprofessur für Biomedizinische Technik Jürgen Herrler Department of Neuroradiology Peter Linz Institute of Radiology Angelika Mennecke Department of Neuroradiology Manuel Schmidt Department of Neuroradiology Arnd Dörfler Department of Neuroradiology Michael Uder Lehrstuhl für Diagnostische Radiologie Moritz Zaiß Professur für Multimodale Bildgebung in der klinischen Forschung Armin Michael Nagel Professur für metabolische und funktionelle MR-Bildgebung

How to cite

APA:

Liebert, A., Tkotz, K., Herrler, J., Linz, P., Mennecke, A., German, A.,... Nagel, A.M. (2021). Whole-brain quantitative CEST MRI at 7T using parallel transmission methods and B1+ correction. Magnetic Resonance in Medicine. https://doi.org/10.1002/mrm.28745

MLA:

Liebert, Andrzej, et al. "Whole-brain quantitative CEST MRI at 7T using parallel transmission methods and B1+ correction." Magnetic Resonance in Medicine (2021).

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