Monitoring and compensating phase imperfections in cine balanced steady-state free precession

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 m...

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Bibliographic Details
Published in:Magnetic resonance in medicine 2013-12, Vol.70 (6), p.1567-1579
Main Authors: Fischer, Rudolf Fritz, Barmet, Christoph, Rudin, Markus, Boesiger, Peter, Pruessmann, Klaas Paul, Kozerke, Sebastian
Format: Article
Language:English
Subjects:
Algorithms
balanced SSFP
Cameras
cine imaging
eddy currents
Heart - anatomy & histology
Humans
Image Enhancement - methods
Image Interpretation, Computer-Assisted - methods
magnetic field monitoring
Magnetic Resonance Imaging, Cine - instrumentation
Magnetic Resonance Imaging, Cine - methods
Pattern Recognition, Automated - methods
Phantoms, Imaging
Reproducibility of Results
Sensitivity and Specificity
steady-state free precession
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Summary: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.
ISSN:0740-3194
1522-2594
DOI:10.1002/mrm.24606