Analysis of different phase unwrapping methods to optimize quantitative susceptibility mapping in the abdomen

2019 ◽  
Vol 82 (6) ◽  
pp. 2077-2089 ◽  
Author(s):  
Eric Bechler ◽  
Julia Stabinska ◽  
Hans‐Jörg Wittsack
2021 ◽  
Author(s):  
Oliver C. Kiersnowski ◽  
Anita Karsa ◽  
Stephen J. Wastling ◽  
John S. Thornton ◽  
Karin Shmueli

Purpose: Quantitative susceptibility mapping (QSM) is increasingly used for clinical research where oblique image acquisition is commonplace but its effects on QSM accuracy are not well understood. Theory and Methods: The QSM processing pipeline involves defining the unit magnetic dipole kernel, which requires knowledge of the direction of the main magnetic field B0 with respect to the acquired image volume axes. The direction of B0 is dependent upon the axis and angle of rotation in oblique acquisition. Using both a numerical brain phantom and in-vivo acquisitions, we analysed the effects of oblique acquisition on magnetic susceptibility maps. We compared three tilt correction schemes at each step in the QSM pipeline: phase unwrapping, background field removal and susceptibility calculation, using the root-mean-squared error and QSM-tuned structural similarity index (XSIM). Results: Rotation of wrapped phase images gave severe artefacts. Background field removal with projection onto dipole fields gave the most accurate susceptibilities when the field map was first rotated into alignment with B0. LBV and VSHARP background field removal methods gave accurate results without tilt correction. For susceptibility calculation, thresholded k-space division, iterative Tikhonov regularisation and weighted linear total variation regularisation all performed most accurately when local field maps were rotated into alignment with B0 before susceptibility calculation. Conclusion: For accurate QSM, oblique acquisition must be taken into account. Rotation of images into alignment with B0 should be carried out after phase unwrapping and before background field removal. We provide open-source tilt-correction code to incorporate easily into existing pipelines: https://github.com/o-snow/QSM_TiltCorrection.git.


2013 ◽  
Vol 27 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Wei Li ◽  
Alexandru V. Avram ◽  
Bing Wu ◽  
Xue Xiao ◽  
Chunlei Liu

2020 ◽  
Author(s):  
Yang Gao ◽  
Xuanyu Zhu ◽  
Bradford A. Moffat ◽  
Rebecca Glarin ◽  
Alan H. Wilman ◽  
...  

NeuroImage ◽  
2016 ◽  
Vol 125 ◽  
pp. 1131-1141 ◽  
Author(s):  
Berkin Bilgic ◽  
Luke Xie ◽  
Russell Dibb ◽  
Christian Langkammer ◽  
Aysegul Mutluay ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document