Title
Advances in gradient echo myelin water imaging at 3T and 7T.
Abstract
Gradient echo myelin water imaging (GRE-MWI) is an MRI technique to measure myelin concentration and involves the analysis of signal decay characteristics of the multi-echo gradient echo data. The method provides a myelin water fraction as a quantitative biomarker for myelin. In this work, a new sequence and post-processing methods were proposed to generate high quality GRE-MWI images at 3T and 7T. In order to capture the rapidly decaying myelin water signals, a bipolar readout GRE sequence was designed with "gradient pairing," compensating for the eddy current effects. The flip angle dependency from the multi-compartmental T1 effects was explored and avoided using a 2D multi-slice acquisition with a long TR. Additionally, the sequence was tested for the effects of inflow and magnetization transfer and demonstrated robustness to these error sources. Lastly, the temporal and spatial B0 inhomogeneity effects were mitigated by using the B0 navigator and field inhomogeneity corrections. Using the method, high-quality myelin water images were successfully generated for the in-vivo human brain at both field strengths. When the myelin water fraction at 3T and 7T were compared, they showed a good correlation (R2≥ 0.88; p < 0.001) with a larger myelin water fraction at 7T. The proposed method also opens the possibility of high resolution (isotropic 1.5 mm resolution) myelin water mapping at 7T.
Year
DOI
Venue
2019
10.1016/j.neuroimage.2018.11.040
NeuroImage
Keywords
Field
DocType
Myelin,Myelin water imaging,T2* relaxation,Bipolar acquisition,Multi-echo gradient echo,Gradient pairing
Psychology,Flip angle,Cognitive psychology,Robustness (computer science),Pairing,Magnetization transfer,Eddy current,Nuclear magnetic resonance,Myelin
Journal
Volume
ISSN
Citations 
188
1053-8119
1
PageRank 
References 
Authors
0.36
6
10
Name
Order
Citations
PageRank
Hyeong-Geol Shin182.16
Se-Hong Oh262.12
Masaki Fukunaga331927.13
Yoonho Nam4253.70
doohee lee511.04
Woojin Jung6273.33
Minju Jo710.36
Sooyeon Ji871.55
Joon Yul Choi9244.32
Jongho Lee10746.15