Motion-insensitive susceptibility weighted imaging

Area of Science:

• Medical Imaging
• Neuroimaging
• Radiology

Background:

• Susceptibility-weighted imaging (SWI) is sensitive to magnetic field inhomogeneities.
• Head movement during MRI can severely corrupt SWI quality, even with prospective motion correction.
• Conventional SWI sequences often struggle with motion artifacts, limiting their clinical utility in certain patient populations.

Purpose of the Study:

• To develop and evaluate a motion-robust SWI technique.
• To enable SWI that is resilient to significant head movement.
• To compare a novel sequence with conventional methods for motion-induced artifacts.

Main Methods:

• Investigated 2D interleaved snapshot EPI for motion-robust SWI, comparing it with conventional 2D EPI and 3D sequences.
• Applied prospective motion correction using a markerless optical tracker to all sequences.
• Performed retrospective motion correction on repeated signal averages.
• Evaluated sequences at 3 Tesla using controlled motion experiments and a tumor patient.

Main Results:

• Interleaved snapshot EPI demonstrated minimal intraslice phase discrepancies due to its short temporal footprint.
• Image quality of 3D sequences and conventional 2D EPI was poor with head motion (5-8° rotations) unless the motion axis was parallel to B₀.
• Interleaved snapshot EPI with prospective and retrospective motion correction yielded consistent image quality irrespective of motion, with lesion depiction comparable to 3D EPI.

Conclusions:

• Susceptibility-based imaging is vulnerable to head movement despite prospective motion correction.
• 2D interleaved snapshot EPI is a superior alternative for motion-prone patients.
• This technique offers motion-insensitive SWI when combined with prospective and retrospective motion correction, improving diagnostic accuracy.