Convex gradient optimization for increased spatiotemporal resolution and improved accuracy in phase contrast MRI
- Author(s): Middione, MJ
- Wu, HH
- Ennis, DB
- et al.
Published Web Locationhttps://doi.org/10.1002/mrm.25059
© 2013 Wiley Periodicals, Inc. Purpose: To evaluate convex gradient optimization (CVX) for increased spatiotemporal resolution and improved accuracy for phase-contrast MRI (PC-MRI).Methods: A conventional flow-compensated and flowencoded (FCFE) PC-MRI sequence was compared with a CVX PC-MRI sequence using numerical simulations, flow phantom experiments, and in vivo experiments. Flow measurements within the ascending aorta, main pulmonary artery, and right/left pulmonary arteries of normal volunteers (N = 10) were acquired at 3T and analyzed using a conventional FCFE sequence and a CVX sequence with either higher spatial resolution or higher temporal resolution. All sequences mitigated chemical shift-induced phase errors and used equivalent breath-hold durations.Results: Chemical shift-optimized PC-MRI has increased sequence efficiency when using CVX, which can provide either higher spatial or higher temporal resolution compared with conventional FCFE PC-MRI. Numerical simulations, flow phantom experiments, and in vivo experiments indicate that CVX measurements of total flow and peak velocity are increased and more accurate when compared with FCFE.Conclusion: CVX PC-MRI increases sequence efficiency while reducing chemical shift-induced phase errors. This can be used to provide either higher spatial or higher temporal resolution than conventional chemical shift-mitigated PC-MRI methods to provide more accurate measurements of blood flow and peak velocity.