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Technical Note
Effect of flip angle on volume flow measurement with nontriggered phase-contrast MR: In vivo evaluation in carotid and basilar arteries
Article first published online: 22 APR 2009
DOI: 10.1002/jmri.21748
Copyright © 2009 Wiley-Liss, Inc.
Additional Information
How to Cite
Tanaka, H., Fujita, N., Takahashi, H., Sakai, M., Nagao, T., Murase, K. and Nakamura, H. (2009), Effect of flip angle on volume flow measurement with nontriggered phase-contrast MR: In vivo evaluation in carotid and basilar arteries. J. Magn. Reson. Imaging, 29: 1218–1223. doi: 10.1002/jmri.21748
Publication History
- Issue published online: 22 APR 2009
- Article first published online: 22 APR 2009
- Manuscript Accepted: 4 FEB 2009
- Manuscript Received: 30 OCT 2008
- Abstract
- Article
- References
- Cited By
Keywords:
- phase-contrast;
- magnetic resonance;
- blood flow
Abstract
Purpose
To evaluate the effect of flip angle on volume flow rate measurements obtained with nontriggered phase-contrast magnetic resonance imaging (MRI) in vivo.
Materials and Methods
We prospectively measured volume flow rates of the bilateral internal carotid artery and the basilar artery with cine and nontriggered phase-contrast MRI. For nontriggered phase-contrast imaging, flip angles of 4, 15, 60, and 90° were used for 40 volunteers and of 8, 15, and 30° for 54 volunteers. Lumen boundaries were semiautomatically determined by pulsatility-based segmentation using cine phase-contrast MRI. Identical lumen boundaries were used for nontriggered phase-contrast imaging.
Results
The ratio of volume flow rate obtained with nontriggered phase-contrast imaging to that obtained with cine phase-contrast imaging significantly increases with an increase in the flip angle. The mean ratios lie within a relatively narrow range of ±15% with a wide range of flip angles of 8–90°. As the flip angle increases, ghost artifacts become prominent and signal-to-noise and contrast-to-noise ratios increase.
Conclusion
Flip angles between 8 and 60° are most appropriate for nontriggered phase-contrast MR measurements in the internal carotid and the basilar artery. J. Magn. Reson. Imaging 2009;29:1218–1223. © 2009 Wiley-Liss, Inc.