Towards accurate MRF T2 in structured material at 0.55T using MT-suppressed excitations

Zhibo Zhu; Nam G Lee; Krishna S Nayak

doi:10.1016/j.mri.2025.110444

Towards accurate MRF T₂ in structured material at 0.55T using MT-suppressed excitations

Magn Reson Imaging. 2025 Oct:122:110444. doi: 10.1016/j.mri.2025.110444. Epub 2025 Jun 9.

Authors

Zhibo Zhu¹, Nam G Lee², Krishna S Nayak³

Affiliations

¹ Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, United States. Electronic address: zhibozhu@usc.edu.
² Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States.
³ Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, United States; Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States.

PMID: 40499695
DOI: 10.1016/j.mri.2025.110444

Abstract

Purpose: To develop a 0.55 T FISP-MRF approach that provides more accurate T₂ maps in structured materials (e.g. white matter).

Method: Non-selective low-bandwidth excitation strategies that reduce on-resonance MT effects were implemented. Dictionaries were simulated using a conventional single pool model. Estimated MRF T₂ maps using the non-selective approach with 2 pulse durations were compared against MRF T₂ maps using the conventional slab-selective approach, and against conventional but slow reference measurements.

Results: The proposed approach substantially reduces T₂ underestimation in white matter from ∼40 % to <10 % without compromising precision.

Conclusion: The use of non-selective low-bandwidth excitations substantially reduces MT effects in 0.55T FISP-MRF, enabling use of a single pool model. This is particularly important for MRF at low field strengths and in structured materials such as white matter.

Keywords: 0.55T MRI; FISP-MRF; Magnetization transfer effects.

MeSH terms

Algorithms
Brain* / anatomy & histology
Brain* / diagnostic imaging
Computer Simulation
Humans
Image Processing, Computer-Assisted* / methods
Magnetic Resonance Imaging* / methods
Phantoms, Imaging
Reproducibility of Results
White Matter* / anatomy & histology
White Matter* / diagnostic imaging