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Rapid measurement and correction of phase errors from B 0 eddy currents: Impact on image quality for non‐cartesian imaging
Author(s) -
Brodsky Ethan K.,
Klaers Jessica L.,
Samsonov Alexey A.,
Kijowski Richard,
Block Walter F.
Publication year - 2013
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24264
Subject(s) - cartesian coordinate system , eddy current , scanner , image quality , physics , phase (matter) , quality (philosophy) , eddy current testing , azimuth , computer science , optics , nuclear magnetic resonance , algorithm , artificial intelligence , image (mathematics) , mathematics , geometry , quantum mechanics
Non‐Cartesian imaging sequences and navigational methods can be more sensitive to scanner imperfections that have little impact on conventional clinical sequences, an issue which has repeatedly complicated the commercialization of these techniques by frustrating transitions to multicenter evaluations. One such imperfection is phase errors caused by resonant frequency shifts from eddy currents induced in the cryostat by time‐varying gradients, a phenomenon known as B 0 eddy currents. These phase errors can have a substantial impact on sequences that use ramp sampling, bipolar gradients, and readouts at varying azimuthal angles. We present a method for measuring and correcting phase errors from B 0 eddy currents and examine the results on two different scanner models. This technique yields significant improvements in image quality for high‐resolution joint imaging on certain scanners. This result suggests that correcting short‐time B 0 eddy currents that do not affect conventional clinical sequences may simplify the adoption of non‐Cartesian methods. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.