Motion correction for diffusion weighted SMS imaging

Purpose Prospective motion correction (PMC) and retrospective motion correction (RMC) have different advantages and limitations. The present work aims to combine the advantages of both for rigid body motion, aiming at correcting for faster motions than was previously achievable. Additionally, it provides insights into the effects of motion on pulse sequences and MR signals with a goal of further improving motion correction in the future. Methods The effective encoding trajectory and a global phase offset in a moving object are calculated based on complete gradient waveforms of an arbitrary sequence and a continuous motion model. These data are used to feed the forward signal model, which is then used in iterative image reconstruction to suppress the artifacts still present after the PMC. Results Verification experiments with a rotation phantom and in vivo were performed. Predictions of simulated motion artifacts for PMC based on sequence waveforms are very accurate. The performance at combined PMC+RMC is limited by Nyquist violations in the sampled k‐space and can be compensated by oversampling. Conclusion The combined correction results in better images than pure PMC in the presence of fast motion. The predictions of artifacts are very accurate, allowing for comparing sequences or protocols in simulations. The observed artifacts due to Nyquist violations are expected to be corrected by utilizing parallel imaging.

Section: Introductionmentioning

confidence: 99%

“…Therefore, multishot DW EPI required additional post-processing. 16 Compared to PMC, the retrospective correction is less influenced by the latency of the motion data. Some data-driven methods 11,17,18 model the motion directly from the MR data.…”

Section: Introductionmentioning

confidence: 99%

Combining prospective and retrospective motion correction based on a model for fast continuous motion

Hucker

Dacko

Zaitsev

2021

“…Combining SMS and segmented DWI, several algorithms have been proposed for shot‐to‐shot phase corrections with navigated, 44 self‐navigated, 45,46 and navigator‐free 47 approaches. Further macroscopic motion corrections have been developed using external tracking devices and intermediate non‐diffusion‐weighted navigators 48 . Recent approaches exploit SMS acceleration for single‐shot EPI to obtain signal support in the slice direction and propose SMS‐to‐volume registration for 3D rigid motion‐corrected fMRI 49,50 and diffusion tensor fitting 51 …”

Section: Introductionmentioning

confidence: 99%

Segmented simultaneous multi‐slice diffusion‐weighted imaging with navigated 3D rigid motion correction

Steinhoff

Setsompop

Mertins

et al. 2021

Purpose To improve the robustness of diffusion‐weighted imaging (DWI) data acquired with segmented simultaneous multi‐slice (SMS) echo‐planar imaging (EPI) against in‐plane and through‐plane rigid motion. Theory and Methods The proposed algorithm incorporates a 3D rigid motion correction and wavelet denoising into the image reconstruction of segmented SMS‐EPI diffusion data. Low‐resolution navigators are used to estimate shot‐specific diffusion phase corruptions and 3D rigid motion parameters through SMS‐to‐volume registration. The shot‐wise rigid motion and phase parameters are integrated into a SENSE‐based full‐volume reconstruction for each diffusion direction. The algorithm is compared to a navigated SMS reconstruction without gross motion correction in simulations and in vivo studies with four‐fold interleaved 3‐SMS diffusion tensor acquisitions. Results Simulations demonstrate high fidelity was achieved in the SMS‐to‐volume registration, with submillimeter registration errors and improved image reconstruction quality. In vivo experiments validate successful artifact reduction in 3D motion‐compromised in vivo scans with a temporal motion resolution of approximately 0.3 s. Conclusion This work demonstrates the feasibility of retrospective 3D rigid motion correction from shot navigators for segmented SMS DWI.

“…Markers also increase subject preparation time and may have adverse effects due to marker detachment, slippage, or loss of visual contact. 24,25 Since optical tracking is independent of the MR system, some type of cross-calibration is required between the tracking and MR systems that aligns their frames of reference.…”

Section: Introductionmentioning

confidence: 99%

“…Unfortunately, there may be a substantial overlap between patients non‐compliant with markers and those prone to move during imaging, including small children. Markers also increase subject preparation time and may have adverse effects due to marker detachment, slippage, or loss of visual contact 24,25 . Since optical tracking is independent of the MR system, some type of cross‐calibration is required between the tracking and MR systems that aligns their frames of reference.…”

Section: Introductionmentioning

confidence: 99%

Prospective motion correction for diffusion weighted EPI of the brain using an optical markerless tracker

Berglund

Niekerk

Rydén

et al. 2020