High-resolution distortion-free diffusion imaging using hybrid spin-warp and echo-planar PSF-encoding approach.

In, Myung-Ho; Posnansky, Oleg; Speck, Oliver

doi:10.1016/j.neuroimage.2017.01.008

by Myung-Ho In, Oleg Posnansky, Oliver Speck

Abstract:

High-resolution diffusion-weighted imaging (DWI) has great potential to provide unique information about tissue microstructure in-vivo. Although single-shot echo-planar imaging (EPI) is a most popular tool for DWI, its application for high-resolution DWI is limited due to T2* blurring and susceptibility- and eddy-current-induced geometric distortions, especially at ultra-high field (UHF) such as 7T. In this study, we adapt a hybrid spin-warp and echo-planar encoding strategy inspired by point spread function (PSF) mapping and optimize it for high-resolution and distortion-free diffusion imaging applications. More specifically, a 2D navigator echo is added into the original sequence for shot-to-shot motion-induced phase error estimation and correction. The spatial encoding is shared between the PSF and the EPI phase encoding dimension allowing short echo trains to preserve the diffusion and navigator signals efficiently at UHF, where T2 decay is relatively fast. In addition, variable k-space spacing was applied in the PSF dimension and combined with parallel imaging in the EPI-PE dimension to further accelerate the PSF acquisition. The results demonstrate that this method can yield isotropic submillimeter resolution without T2* blurring and geometric distortions at 7T and enables a clear and detailed delineation of human brain structures in-vivo with the diffusion contrasts. In addition, results of the proposed approach for high-resolution diffusion imaging at 3T are presented.

Reference:

High-resolution distortion-free diffusion imaging using hybrid spin-warp and echo-planar PSF-encoding approach. (Myung-Ho In, Oleg Posnansky, Oliver Speck), In NeuroImage, volume 148, 2017.

Bibtex Entry:

@article{in_high-resolution_2017,
	title = {High-resolution distortion-free diffusion imaging using hybrid spin-warp and echo-planar {PSF}-encoding approach.},
	volume = {148},
	copyright = {Copyright (c) 2017 Elsevier Inc. All rights reserved.},
	issn = {1095-9572 1053-8119},
	doi = {10.1016/j.neuroimage.2017.01.008},
	abstract = {High-resolution diffusion-weighted imaging (DWI) has great potential to provide unique information about tissue microstructure in-vivo. Although single-shot echo-planar imaging (EPI) is a most popular tool for DWI, its application for high-resolution DWI is limited due to T2* blurring and susceptibility- and eddy-current-induced geometric distortions, especially at ultra-high field (UHF) such as 7T. In this study, we adapt a hybrid spin-warp and echo-planar encoding strategy inspired by point spread function (PSF) mapping and optimize it for high-resolution and distortion-free diffusion imaging applications. More specifically, a 2D navigator echo is added into the original sequence for shot-to-shot motion-induced phase error estimation and correction. The spatial encoding is shared between the PSF and the EPI phase encoding dimension allowing short echo trains to preserve the diffusion and navigator signals efficiently at UHF, where T2 decay is relatively fast. In addition, variable k-space spacing was applied in the PSF dimension and combined with parallel imaging in the EPI-PE dimension to further accelerate the PSF acquisition. The results demonstrate that this method can yield isotropic submillimeter resolution without T2* blurring and geometric distortions at 7T and enables a clear and detailed delineation of human brain structures in-vivo with the diffusion contrasts. In addition, results of the proposed approach for high-resolution diffusion imaging at 3T are presented.},
	language = {eng},
	journal = {NeuroImage},
	author = {In, Myung-Ho and Posnansky, Oleg and Speck, Oliver},
	month = mar,
	year = {2017},
	pmid = {28065851},
	keywords = {*Diffusion imaging, *Diffusion-weighted image, *High resolution, *Point spread function, *Ultra-high field, Algorithms, Artifacts, Brain Mapping, Computer-Assisted/*methods, Diffusion Magnetic Resonance Imaging/*methods, Echo-Planar Imaging/*methods, Humans, Image Enhancement/methods, Image Processing, Motion, Multimodal Imaging, Neuroimaging/methods},
	pages = {20--30}
}