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Cardiac 4D phase-contrast CMR at 9.4 T using self-gated ultra-short echo time (UTE) imaging
M Krämer1, A G Motaal2, K-H Herrmann3
1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Philosophenweg 3, D-07743, Jena, Germany. martinkraemer84@gmail.com.
Summary
A new self-gated 4D phase contrast (PC) cardiovascular magnetic resonance (CMR) ultra-short echo-time (UTE) technique improves mouse heart imaging. This method offers better signal-to-noise ratio (SNR) and image quality compared to traditional ECG-triggered sequences.
Area of Science:
- Cardiovascular Magnetic Resonance Imaging
- Medical Physics
- Biomedical Engineering
Background:
- Time-resolved 4D phase contrast (PC) cardiovascular magnetic resonance (CMR) in mice is limited by long scan times and motion artifacts.
- ECG-gating in small rodents is challenging due to rapid heart rates and small anatomical structures.
Purpose of the Study:
- To implement and assess a retrospectively self-gated 4D PC radial ultra-short echo-time (UTE) acquisition scheme.
- To overcome technical challenges in mouse cardiac MRI, improving scan efficiency and image quality.
Main Methods:
- Acquisition of cardiac 4D PC CMR images in mice at 9.4T using a self-gated radial center-out UTE sequence.
- Comparison with a standard Cartesian 4D PC fast low angle shot (FLASH) sequence.
- Validation using a flow phantom with variable pump rates.
Main Results:
- The UTE technique demonstrated reduced artifacts and improved SNR (LV: 8.9±2.5, MC: 15.7±1.9) compared to FLASH (LV: 5.6±1.2, MC: 10.1±1.4).
- Comparable flow velocities were observed in the flow phantom and animal aorta/pulmonary artery between UTE and FLASH.
- Higher gating efficiency was achieved with the UTE sequence (61.8±11.5%) versus FLASH (48.5±4.9%).
Conclusions:
- The self-gated 4D PC UTE sequence provides robust and accurate in vivo flow velocity mapping of the mouse heart at high magnetic fields.
- This novel sequence enhances SNR, gating efficiency, and image quality while reducing artifacts compared to conventional ECG-triggered 4D PC FLASH sequences.