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Time-resolved TOF MR angiography in mice using a prospective 3D radial double golden angle approach
Aurelien J Trotier1, William Lefrançois, Emeline J Ribot
1Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS/Université Bordeaux Segalen, Bordeaux Cedex, France.
Purpose:
To develop an undersampled anatomical, three-dimensional (3-D) time-resolved magnetic resonance angiography (MRA) method for small animals based on time-of-flight (TOF) effect and radial sampling.
Methods:
Mouse carotid arteries and Circle of Willis images were acquired on a 7T scanner with an electrocardiogram (ECG)-triggered sequence. Preliminary experiments were used to generate an approximately uniform distribution of radial projections with a first golden angle and to produce anatomical TOF images. A second golden angle ratio between consecutive projections of cine acquisitions was added to make it possible to use a temporal filter during reconstruction of time-resolved angiography. A decreasing number of projections were tested, and their impact on signal-to-noise ratio (SNR) and spatial resolution was assessed.
Results:
In anatomical MRA, the undersampled radial approach efficiently allows fast acquisition of mouse angiogram in 3D (22 sec). It was also only slightly sensitive to motion and flow artifacts. The time-resolved sequence can be performed with only 2,500 projections per cine and a temporal resolution under 4 ms in a relatively short acquisition time (less than 5 min).
Conclusion:
This technique simultaneously provided high 3D isotropic spatial resolution and excellent temporal resolution with a good SNR level, allowing blood flow to be visualized in a restricted acquisition time.
Insights
This study introduces a fast 3D time-resolved magnetic resonance angiography (MRA) technique for small animals. The novel method enables high-resolution imaging of blood flow with excellent temporal and spatial resolution in minimal time.
Area of Science:
- Biomedical Imaging
- Magnetic Resonance Imaging
- Angiography
Background:
- Small animal imaging is crucial for preclinical research.
- Developing advanced Magnetic Resonance Angiography (MRA) techniques is essential for visualizing vascular structures.
- Time-of-flight (TOF) MRA with radial sampling offers potential for rapid 3D imaging.
Purpose of the Study:
- To develop an undersampled, 3D, time-resolved MRA method for small animals.
- To leverage the time-of-flight (TOF) effect and radial sampling for enhanced imaging.
- To achieve high spatial and temporal resolution in small animal vascular imaging.
Main Methods:
- Utilized a 7T scanner with an ECG-triggered sequence for image acquisition.
- Employed a golden angle radial sampling strategy for efficient data acquisition.
- Developed a temporal filtering approach during reconstruction for time-resolved angiography.
Main Results:
- Achieved fast 3D anatomical MRA acquisition of mouse vasculature in 22 seconds.
- Demonstrated robustness against motion and flow artifacts.
- Enabled time-resolved MRA with a temporal resolution under 4 ms in under 5 minutes.
Conclusions:
- The developed technique provides high 3D isotropic spatial resolution and excellent temporal resolution.
- Achieved good signal-to-noise ratio (SNR) for clear visualization of blood flow.
- Offers a powerful tool for small animal vascular imaging within restricted acquisition times.
