Real time high spatial-temporal resolution flow imaging with spiral MRI using auto-calibrated SENSE.
A novel spiral phase contrast technique was developed for high temporal and spatial resolution imaging of blood flow without cardiac gating. Spiral sampling of k-space has excellent flow properties and acquisition speed. Parallel imaging using the coil sensitivity maps can be used to reduce the imaging duration at the cost of SNR. An auto-calibrated spiral sensitivity encoding method is introduced and used for reconstruction of phase contrast images. Phase estimation for a simulated phantom using data from various acceleration rates was compared to the true phase map. To study the accuracy of the flow estimate with parallel image reconstruction, a high resolution cardiac gated experiment was performed and a subset of under-sampled data were reconstructed. The real-time experiments were performed to measure blood velocity in the ascending aorta and through the aortic valve with high spatial and temporal resolution. Temporal resolution of the flow images was improved by a factor of at least three with no cardiac gating signal with preserved spatial resolution. The results demonstrate the potential of using the technique for real-time flow imaging with improved spatial and temporal resolution.
Nezafat
Reza
R
Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Kellman
Peter
P
Derbyshire
John
J
McVeigh
Elliot
E