- Poster presentation
- Open Access
Navigator techniques for coronary MRA at 7 T
https://doi.org/10.1186/1532-429X-12-S1-P49
© Agarwal et al; licensee BioMed Central Ltd. 2010
- Published: 21 January 2010
Keywords
- Right Coronary Artery
- Surface Coil
- Anterior Chest Wall
- Magnetic Resonance Angiography Image
- Coronary Magnetic Resonance Angiography
Introduction
Performance of the respiratory navigator is critical in coronary magnetic resonance angiography (MRA). At 7 T, the performance of a conventional 2D-selective navigator is adversely affected by field inhomogeneities and limited volumetric coverage of transmit/receive surface coils which must be used on systems without transmit array capability. Therefore, two navigator approaches, a 2D-selective navigator optimized for 7 T and a non-selective navigator that is less susceptible to field inhomogeneities, were implemented. Coronary MRAs were obtained with both techniques and quantitatively compared.
Purpose
To compare 7 T coronary MRAs obtained with an optimized 2D-selective and a new non-selective navigator approach.
Methods
Pulse sequence diagram for (a) 2D-selective navigator and (b) non-selective navigator.
Timing diagram for (a) 2D-selective navigator and (b) non-selective navigator.
Results
Results from quantitative data analysis of coronary MRA.
2D-selective pencil beam navigator | Non-selective navigator | |
---|---|---|
SNR blood | 30.1 ± 17.0 | 24.8 ± 14.5 |
RCA vessel length (cm) | 7.47 ± 2.84 | 6.49 ± 1.29 |
RCA vessel sharpness (%) | 58 ± 9 | 53 ± 5 |
RCA vessel diameter (mm) | 2.86 ± 0.25 | 2.88 ± 0.26 |
CNR | 25.3 ± 15.2 | 20.8 ± 14.2 |
Acquisition time (sec) | 560 ± 210 | 508 ± 210 |
Navigator efficiency (%) | 52 ± 22 | 51 ± 12 |
Reformatted RCA using (a) 2D-selective pencil beam navigator and (b) non-selective navigator.
Conclusion
The use of navigator technology for respiratory motion suppression at 7 T is not straightforward. However, 7 T-specific optimizations of the 2D-selective navigator and coil related modifications in navigator localization permit the reliable acquisition of free-breathing coronary MRA at 7 T. The new non-selective navigator is a simple valuable alternative and its coronary MRA image quality approaches that obtained with the 2D-selective navigator.
Authors’ Affiliations
Copyright
This article is published under license to BioMed Central Ltd.