Analysis of temperature dependence of background phase errors in phase-contrast cardiovascular magnetic resonance

Journal of Cardiovascular Magnetic Resonance

Technical Notes

S Johanna Vannesjo¹  Klaas P Pruessmann¹  Julia Busch¹  Sebastian Kozerke²  Christoph Barmet³ 

[1] Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland;Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland;Division of Imaging Science and Biomedical Engineering, King’s College London, London, UK;Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland;Skope Magnetic Resonance Technologies, Zurich, Switzerland;

关键词: Cardiovascular magnetic resonance;    Phase-contrast;    4D flow;    Background phase error;    Thermal stability;    Magnetic field monitoring;   

DOI  :  10.1186/s12968-014-0097-6

 received in 2014-06-11, accepted in 2014-11-14,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundThe accuracy of phase-contrast cardiovascular magnetic resonance (PC-CMR) can be compromised by background phase errors. It is the objective of the present work to provide an analysis of the temperature dependence of background phase errors in PC-CMR by means of gradient mount temperature sensing and magnetic field monitoring.MethodsBackground phase errors were measured for various temperatures of the gradient mount using magnetic field monitoring and validated in a static phantom. The effect of thermal changes during k-space acquisition was simulated and confirmed with measurements in a stationary phantom.ResultsThe temperature of the gradient mount was found to increase by 20–30 K during PC-CMR measurements of 6–12 min duration. Associated changes in background phase errors of up to 11% or 0.35 radian were measured at 10 cm from the magnet’s iso-center as a result of first order offsets. Zeroth order phase errors exhibited little thermal dependence.ConclusionsIt is concluded that changes in gradient mount temperature significantly modify background phase errors during PC-CMR with high gradient duty cycle. Since temperature increases significantly during the first minutes of scanning the results presented are also of relevance for single-slice or multi-slice PC-CMR scans. The findings prompt for further studies to investigate advanced correction methods taking into account gradient temperature and/or the use of concurrent field-monitoring to map gradient-induced fields throughout the scan.

【 授权许可】

Unknown   
© Busch et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.