Evaluation of an interleaved acquisition scheme for improved robustness of channel-wise relative B1+ mapping at 7 T

Egger N, Ruck L, Nagelstraßer S, Schirmer J, Wildenberg S, Bitz A, Herrler J, Schmitter S, Uder M, Nagel AM (2025)

Publication Type: Journal article

Publication year: 2025

Journal

DOI: 10.1002/mrm.70101

Abstract

Purpose: The purpose was to evaluate, whether an interleaved acquisition scheme for a fast relative (Formula presented.) mapping method at 7 T reduces the likelihood of errors from exceeding the linear flip angle (FA) regime compared to a conventional sequential acquisition. Methods: Simulations of a channel-wise relative (Formula presented.) mapping sequence were performed for sequential and interleaved acquisition schemes at different reference voltages (≙ different FAs). The simulations were performed for a phantom, the heart and the prostate and were based on 7 T ground-truth (GT) (Formula presented.) data acquired with an actual FA imaging sequence (phantom) or obtained from electromagnetic field simulations (heart/prostate). Acquisition schemes were evaluated based on their signal linearity by calculating a normalized mean FA error between simulated signal intensities and GT (Formula presented.) data. Additionally, validation measurements of relative (Formula presented.) maps with the sequential and interleaved acquisition schemes were acquired for the phantom. Results: Validation measurements showed a good agreement with the simulation results for both acquisition schemes and displayed stronger deviations to the GT (Formula presented.) data for the sequential scheme. The quantitative evaluation yielded higher FA errors for the sequential acquisition scheme for all three regions and all simulated reference voltages. At the same level of error, mean signals were higher for the interleaved acquisition scheme in all cases. Differences between interleaved and sequential acquisition schemes were most pronounced in the steady-state. Conclusion: An interleaved acquisition of channel-wise relative (Formula presented.) maps extends the range of the linear FA regime, reducing the likelihood of errors and increasing the robustness of the approach.

Authors with CRIS profile

Involved external institutions

Fachhochschule Aachen - Aachen University of Applied Sciences Germany (DE) Physikalisch-Technische Bundesanstalt (PTB) Germany (DE)

How to cite

APA:

Egger, N., Ruck, L., Nagelstraßer, S., Schirmer, J., Wildenberg, S., Bitz, A.,... Nagel, A.M. (2025). Evaluation of an interleaved acquisition scheme for improved robustness of channel-wise relative B1+ mapping at 7 T. Magnetic Resonance in Medicine. https://doi.org/10.1002/mrm.70101

MLA:

Egger, Nico, et al. "Evaluation of an interleaved acquisition scheme for improved robustness of channel-wise relative B1+ mapping at 7 T." Magnetic Resonance in Medicine (2025).

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