Fast phase-contrast velocity measurement in the steady state
| Autor: | William R. Overall, Dwight G. Nishimura, Bob S. Hu |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Physics
Steady state (electronics) Phantoms Imaging business.industry media_common.quotation_subject Phase (waves) Aorta Thoracic Steady-state free precession imaging Magnetic Resonance Imaging Imaging phantom Reduction (complexity) Carotid Arteries Optics Flow velocity Reference Values Precession Humans Contrast (vision) Radiology Nuclear Medicine and imaging business Blood Flow Velocity media_common |
| Zdroj: | Magnetic Resonance in Medicine. 48:890-898 |
| ISSN: | 1522-2594 0740-3194 |
| DOI: | 10.1002/mrm.10285 |
| Popis: | A new method of encoding flow velocity as image phase in a refocused steady-state free precession (SSFP) sequence, called steady-state phase contrast (SSPC), can be used to generate velocity images rapidly while retaining high signal. Magnitude images with refocused-SSFP contrast are simultaneously acquired. This technique is compared with the standard method of RF-spoiled phase contrast (PC), and is found to have more than double the phase-signal to phase-noise ratio (PNR) when compared with standard PC at reasonable repetition intervals (TRs). As TR decreases, this advantage increases exponentially, facilitating rapid scans with high PNR efficiency. Rapid switching between the two necessary steady states can be accomplished by the insertion of a single TR interval with no flow-encoding gradient. The technique is implemented in a 2DFT sequence and validated in a phantom study. Preliminary results indicate that further TR reduction may be necessary for high-quality cardiac images; however, images in more stationary structures, such as the descending aorta and carotid bifurcation, exhibit good signal-to-noise ratio (SNR) and PNR. Comparisons with standard-PC images verify the PNR advantage predicted by theory. |
| Databáze: | OpenAIRE |
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