Abstract
Purpose: To evaluate the feasibility of using asymmetric sampling in a three-dimensional, magnetization-prepared, segmented true-FISP (fast imaging with steady-state precession) sequence in order to reduce the sensitivity to resonance offsets, while simultaneously improving imaging speed. Materials and Methods: Asymmetric sampling reduces the repetition time, leading to reduced resonance offset effects and improved resolution in a fixed imaging time. However, it introduces additional phase terms due to blood flow, which can cause image artifacts. Computer simulations were performed to study the off-resonance and flow effects of asymmetric sampling in true-FISP. Coronary artery imaging was performed in healthy volunteers. Results: Simulations and volunteer studies show that image artifacts due to flow-induced phase variations may be acceptable at low velocities. Volunteer studies demonstrate that relatively high-resolution coronary artery images can then be acquired within a single breath-hold with segmented three-dimensional true-FISP imaging using data asymmetry in the readout direction. Conclusion: Asymmetric sampling is a useful modification to true-FISP for reducing the off-resonance artifacts and improving imaging speed when the flow velocities are small.
Original language | English (US) |
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Pages (from-to) | 473-478 |
Number of pages | 6 |
Journal | Journal of Magnetic Resonance Imaging |
Volume | 15 |
Issue number | 4 |
DOIs | |
State | Published - 2002 |
Externally published | Yes |
Keywords
- Asymmetric sampling
- Coronary arteries
- Fast imaging
- MR angiography
- Magnetic resonance imaging
- True-FISP
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging