Premium
Monitoring and compensating phase imperfections in cine balanced steady‐state free precession
Author(s) -
Fischer Rudolf Fritz,
Barmet Christoph,
Rudin Markus,
Boesiger Peter,
Pruessmann Klaas Paul,
Kozerke Sebastian
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.24606
Subject(s) - imaging phantom , amplitude , precession , eddy current , phase (matter) , steady state (chemistry) , physics , offset (computer science) , compensation (psychology) , nuclear magnetic resonance , optics , computational physics , control theory (sociology) , computer science , chemistry , psychology , control (management) , quantum mechanics , astronomy , artificial intelligence , psychoanalysis , programming language
Purpose To analyze and correct for eddy current‐induced phase imperfections in cardiac cine balanced steady‐state free precession (bSSFP) imaging. Methods Eddy current‐induced phase offsets were measured for different phase‐encoding schemes using a higher order dynamic field camera. Based on these measurements, offset phases were corrected for in postprocessing and by run‐time phase compensation applying radiofrequency phase increments and additional compensatory gradient areas. The findings were validated using numerical simulations, phantom experiments, and in vivo cardiac scans. Results Depending on the phase‐encoding scheme, significant eddy current‐induced phase offsets were detected. Time‐varying phase offsets were observed at subsequent excitations leading to steady‐state distortions and hence to profile‐dependent amplitude modulations in k‐space. Taking into account measured k‐space trajectories algebraic image reconstruction allowed compensating imperfect spatial encoding. Correction of amplitude modulations was successfully accomplished by run‐time phase compensation. Conclusion Using magnetic field monitoring, artifacts in cine balanced steady‐state free precession caused by uncompensated eddy current fields can be significantly reduced. Magn Reson Med 70:1567–1579, 2013. © 2013 Wiley Periodicals, Inc.