Work

Mitigating banding artifacts in balanced steady‐state free precession using parallel transmission in a single acquisition

Year: 2025

Type: article

Abstract: Purpose Using parallel transmission (pTx) in ultra‐high field MRI allows efficient radiofrequency pulse designs that can produce uniform excitations. Here, we demonstrate that pTx can simultaneously mitigate non‐uniformity and off‐resonance artifacts in balanced steady‐state free precession sequences at 7 T. Theory and Methods The standard hard excitation pulses of the balanced steady‐state free precession sequence were replaced with two pTx pulses, played out in alternating repetition times. Based on the k T ‐point trajectory, each pulse was designed to produce spatially varying phase distributions that compensate for off‐resonance phase variations accumulated over one repetition time duration, while also mitigating non‐uniformities. Depending on the local ΔB 0 , the different steady‐state signals formed were distributed over two aliased images with a half field‐of‐view shift relative to one another. Using slice‐GRAPPA, these images were disentangled and recombined to produce artifact‐free images. Results Simulations validated the concept showing that a pair of strategically designed pTx pulses can impose a favorable distribution of spatially varying steady‐state. As a proof of principle, experiments performed demonstrated the technical feasibility of the concept in a phantom in the presence of induced phase variations and in vivo. Conclusion With a tailored pair of pTx pulses, it was possible to concurrently mitigate and ΔB 0 non‐uniformities in a thin slab through the brain in a single acquisition. Although further work is needed to extend the coverage and robustness of this method before being adopted more widely, it highlights the potential of utilizing pTx capabilities beyond correction.

Source: Magnetic Resonance in Medicine

DOI: 10.1002/mrm.70106

Authors: Chia‐Yin Wu, Jin Jin, Markus Barth, Martijn A. Cloos

Institutions: The University of Queensland, University of Glasgow, Radboud University Nijmegen, Donders Centre for Cognitive Neuroimaging

Language: English

Topic: Advanced MRI Techniques and Applications

Subfield: Radiology, Nuclear Medicine and Imaging

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,680