Abstract
Purpose
To improve the tag persistence throughout the whole cardiac cycle by providing a constant tag‐contrast throughout all the cardiac phases when using balanced steady‐state free precession (bSSFP) imaging.
Materials and Methods
The flip angles of the imaging radiofrequency pulses were optimized to compensate for the tagging contrast‐to‐noise ratio (Tag‐CNR) fading at later cardiac phases in bSSFP imaging. Complementary spatial modulation of magnetization (CSPAMM) tagging was implemented to improve the Tag‐CNR. Numerical simulations were performed to examine the behavior of the Tag‐CNR with the proposed method, and to compare the resulting Tag‐CNR with that obtained from the more commonly used spoiled gradient echo (SPGR) imaging. A gel phantom, as well as five healthy human volunteers, were scanned on a 1.5T scanner using bSSFP imaging with and without the proposed technique. The phantom was also scanned with SPGR imaging.
Results
With the proposed technique, the Tag‐CNR remained almost constant during the whole cardiac cycle. Using bSSFP imaging, the Tag‐CNR was about double that of SPGR.
Conclusion
The tag persistence was significantly improved when the proposed method was applied, with better Tag‐CNR during the diastolic cardiac phase. The improved Tag‐CNR will support automated tagging analysis and quantification methods. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.