Diffusion‐PEPTIDE: Distortion‐ and blurring‐free diffusion imaging with self‐navigated motion‐correction and relaxometry capabilities. Issue 5 (12th December 2020)

• Record Type: Journal Article
• Authors: Fair, Merlin J.; Liao, Congyu; Manhard, Mary Kate; Setsompop, Kawin
• Is Part Of: Magnetic resonance in medicine. Volume 85:Issue 5(2021)
• Page Start: 2417
• Page End: 2433
• Publication Date: 2020-12-12
• Subjects: blurring‐free -- diffusion imaging -- diffusion‐relaxometry -- distortion‐free -- motion‐robust -- multi‐shot; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.28579
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: To implement the time‐resolved relaxometry PEPTIDE technique into a diffusion acquisition to provide self‐navigated, distortion‐ and blurring‐free diffusion imaging that is robust to motion, while simultaneously providing T2 and T 2 ∗ mapping. Theory and Methods: The PEPTIDE readout was implemented into a spin‐echo diffusion acquisition, enabling reconstruction of a time‐series of T2 ‐ and T 2 ∗ ‐weighted images, free from conventional echo planar imaging (EPI) distortion and blurring, for each diffusion‐encoding. Robustness of PEPTIDE to motion and shot‐to‐shot phase variation was examined through a deliberate motion‐corrupted diffusion experiment. Two diffusion‐relaxometry in vivo brain protocols were also examined: (1)1 × 1 × 3 mm 3 across 32 diffusion directions in 20 min, (2)1.5 × 1.5 × 3.0 mm 3 across 6 diffusion‐weighted images in 3.4 min. T2, T 2 ∗, and diffusion parameter maps were calculated from these data. As initial exploration of the rich diffusion‐relaxometry data content for use in multi‐compartment modeling, PEPTIDE data were acquired of a gadolinium‐doped asparagus phantom. These datasets contained two compartments with different relaxation parameters and different diffusion orientation properties, and T2 relaxation variations across these diffusion directions were explored. Results: Diffusion‐PEPTIDE showed the capability to provide high quality diffusion images and T2 and T 2 ∗ maps from both protocols. The reconstructions were distortion‐free, avoided potential resolution losses exceeding 100% in equivalent EPI acquisitions, and showed tolerance to nearly 30° of rotational motion. Expected variation in T2 values as a function of diffusion direction was observed in the two‐compartment asparagus phantom ( P < .01), demonstrating potential to explore diffusion‐PEPTIDE data for multi‐compartment modeling. Conclusions: Diffusion‐PEPTIDE provides highly robust diffusion and relaxometry data and offers potential for future applications in diffusion‐relaxometry multi‐compartment modeling.