Propeller echo-planar time-resolved imaging with dynamic encoding (PEPTIDE).

Area of Science:

• Magnetic Resonance Imaging
• Image Acquisition Techniques
• Motion Correction

Background:

• Echo-planar time-resolved imaging (EPTI) offers rapid, distortion-free, and blur-free multicontrast imaging and quantitative mapping.
• Existing EPTI methods can be sensitive to patient motion during acquisition.
• Developing motion-robust imaging techniques is crucial for reliable clinical and research applications.

Purpose of the Study:

• To develop a motion-robust extension of EPTI, named PROPELLER EPTI with dynamic encoding (PEPTIDE).
• To incorporate k-space encoding rotations into EPTI to enable shot-to-shot motion correction.
• To assess the robustness of PEPTIDE against various types of subject motion compared to conventional EPTI.

Main Methods:

• PEPTIDE integrates k-space encoding rotations into the EPTI sampling strategy, repeatedly acquiring low-resolution k-space center data.
• Retrospective PEPTIDE datasets were generated from in vivo EPTI data with rotational acquisitions for direct comparison.
• Prospective PEPTIDE datasets were acquired and compared with EPTI under actual subject motion conditions.

Main Results:

• PEPTIDE demonstrated significant robustness to severe subject motion, including large in-plane rotations and translational/through-plane motion (>30° rotation).
• The technique successfully maintained the rapid encoding advantages of EPTI.
• Accurate quantitative maps were calculable even from severely motion-corrupted datasets, with significantly improved image quality over conventional EPTI.

Conclusions:

• The PEPTIDE technique effectively integrates high motion tolerance into the EPTI framework.
• PEPTIDE enables rapid acquisition of distortion-free and blur-free images at multiple echo times, even in the presence of motion.
• This advancement enhances the reliability and applicability of EPTI in challenging imaging scenarios.