Modelling Motion‐Induced Signal Corruption in Steady‐State Diffusion MRI

Journal article

Purpose: Diffusion‐weighted steady‐state free precession (DW‐SSFP) is a diffusion imaging sequence achieving high SNR efficiency. A key challenge for in vivo DW‐SSFP is the sequence's severe motion sensitivity, currently limiting investigations to low or no motion regimes. Here we establish a framework to both (1) model and (2) correct for the impact of subject motion associated with the underlying magnetisation distribution of DW‐SSFP. Theory and Methods: An extended phase graphs (EPG) representation of the 1D DW‐SSFP signal was established incorporating a motion operator describing rigid body and pulsatile motion. The representation was validated using Monte Carlo simulations, and subsequently integrated into a data fitting routine for motion estimation and correction. The fitting routine was evaluated using both simulations and a voxelwise correction applied to in vivo experimental 2D low‐resolution single‐shot timeseries DW‐SSFP data acquired in the human brain in three healthy volunteers, with a tensor reconstructed from the motion‐corrected experimental DW‐SSFP data. Results: The proposed EPG‐motion framework gives excellent agreement to complementary Monte Carlo simulations, demonstrating that diffusion coefficient estimation is robust over a range of motion and SNR regimes. Tensor estimates from the motion‐corrected experimental DW‐SSFP data give good visual agreement to complementary diffusion‐weighted spin‐echo (DW‐SE) data acquired in the same subject, considerably reducing orientation‐dependent motion‐induced biases. Conclusion: Temporal information capturing the evolution of the DW‐SSFP signal can be used to retrospectively (1) estimate subject motion and (2) reconstruct motion‐corrected DW‐SSFP data. Open‐source software is provided, facilitating future investigations into the impact of subject‐motion on DW‐SSFP acquisitions.

Authors: Tendler, BC; Wu, W; Miller, KL; Hess, AT

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Magnetic Resonance in Medicine
• Publication date: 2026-02-27
• Acceptance date: 2026-02-12
• DOI: 10.1002/mrm.70315
• EISSN: 1522-2594
• ISSN: 0740-3194
• Language: English
• Keywords: extended phase graphs; diffusion MRI; diffusion‐weighted steady‐state free precession; motion correction; in vivo; steady‐state diffusion