Multiband accelerated 2D EPI for multi-echo brain QSM at 3 T.

Autor: Kiersnowski OC; Department of Medical Physics and Biomedical Engineering, University College London, London, UK.; Neuroradiology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy., Fuchs P; Department of Medical Physics and Biomedical Engineering, University College London, London, UK., Wastling SJ; Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, London, UK.; Lysholm Department of Neuroradiology, London, UK., Nassar J; Department of Medical Physics and Biomedical Engineering, University College London, London, UK., Thornton JS; Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, London, UK.; Lysholm Department of Neuroradiology, London, UK., Shmueli K; Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
Jazyk: angličtina
Zdroj: Magnetic resonance in medicine [Magn Reson Med] 2025 Jan; Vol. 93 (1), pp. 183-198. Date of Electronic Publication: 2024 Aug 20.
DOI: 10.1002/mrm.30267
Abstrakt: Purpose: Data for QSM are typically acquired using multi-echo 3D gradient echo (GRE), but EPI can be used to accelerate QSM and provide shorter acquisition times. So far, EPI-QSM has been limited to single-echo acquisitions, which, for 3D GRE, are known to be less accurate than multi-echo sequences. Therefore, we compared single-echo and multi-echo EPI-QSM reconstructions across a range of parallel imaging and multiband acceleration factors.
Methods: Using 2D single-shot EPI in the brain, we compared QSM from single-echo and multi-echo acquisitions across combined parallel-imaging and multiband acceleration factors ranging from 2 to 16, with volume pulse TRs from 21.7 to 3.2 s, respectively. For single-echo versus multi-echo reconstructions, we investigated the effect of acceleration factors on regional susceptibility values, temporal noise, and image quality. We introduce a novel masking method based on thresholding the magnitude of the local field gradients to improve brain masking in challenging regions.
Results: At 1.6-mm isotropic resolution, high-quality QSM was achieved using multi-echo 2D EPI with a combined acceleration factor of 16 and a TR of 3.2 s, which enables functional applications. With these high acceleration factors, single-echo reconstructions are inaccurate and artefacted, rendering them unusable. Multi-echo acquisitions greatly improve QSM quality, particularly at higher acceleration factors, provide more consistent regional susceptibility values across acceleration factors, and decrease temporal noise compared with single-echo QSM reconstructions.
Conclusion: Multi-echo acquisition is more robust for EPI-QSM across parallel imaging and multiband acceleration factors than single-echo acquisition. Multi-echo EPI can be used for highly accelerated acquisition while preserving QSM accuracy and quality relative to gold-standard 3D-GRE QSM.
(© 2024 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)
Databáze: MEDLINE
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