Self-navigated prospective motion correction for 3D-EPI acquisition.

Area of Science:

• Magnetic Resonance Imaging
• Neuroimaging Techniques

Background:

• 3D EPI offers advantages over 2D EPI for functional MRI, including reduced artifacts and improved sensitivity.
• However, 3D EPI is more susceptible to motion artifacts, limiting its clinical application.
• Prospective motion correction is crucial for high-quality functional MRI data acquisition.

Purpose of the Study:

• To present a novel self-navigated 3D EPI sequence for prospective motion correction in functional MRI.
• To demonstrate the feasibility of this sequence without additional hardware or specialized pulses.
• To evaluate the performance of the sequence in phantom and in vivo studies.

Main Methods:

• A self-navigated 3D EPI sequence was developed, utilizing acquired partitions to generate a volumetric self-navigator (vSNav).
• Motion estimates from the vSNav were used to prospectively update the field of view (FOV) for subsequent acquisitions.
• The sequence was validated using phantom and in vivo scans on a 3T Skyra scanner, with and without induced motion.

Main Results:

• The self-navigated sequence demonstrated stable motion estimates in both phantom and in vivo experiments.
• Prospective head-pose estimates correlated well with retrospective estimates (FLIRT), with agreement within 0.23 mm and 0.14°.
• The system successfully updated the FOV within approximately 0.7 seconds for phantom and in vivo scans.

Conclusions:

• The proposed self-navigated 3D EPI sequence effectively corrects for motion artifacts in functional MRI.
• Image quality is recovered within a single volume acquisition, regardless of when motion occurs.
• This method offers a hardware-independent solution for prospective motion correction in 3D EPI MRI.