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Single-shot 3D GRASE with cylindrical k-space trajectories.
1Advanced MRI Technologies, Sebastopol, California 95472, USA. sudhir.ramanna@advancedmri.com
Magnetic Resonance in Medicine
|September 26, 2008
Summary
Gradient- and spin-echo (GRASE) imaging uses modified trajectories to reduce brain imaging artifacts. This new cylindrical trajectory significantly lowers susceptibility and distortion, improving image quality and signal-to-noise ratio.
Area of Science:
- Magnetic Resonance Imaging (MRI)
- Neuroimaging Techniques
Background:
- Gradient- and spin-echo (GRASE) imaging is crucial for brain physiology studies.
- Echo-planar imaging (EPI) subsequences in GRASE are prone to image distortions and susceptibility artifacts.
- Artifacts are linked to the duration of EPI subsequences between RF refocusing pulses.
Purpose of the Study:
- To develop advanced GRASE pulse sequences for single-shot 3D brain imaging.
- To reduce image distortions and susceptibility artifacts in GRASE MRI.
- To enhance signal-to-noise ratio (SNR) in brain imaging.
Main Methods:
- Modified Cartesian trajectories to circular (2D) and cylindrical (3D) paths.
- Reduced echo train time using modified trajectories.
- Incorporated "fly-back" trajectories with unipolar readout gradients.
- Evaluated performance in phantom and human brain imaging.
Main Results:
- Modified cylindrical trajectory significantly reduced susceptibility artifacts.
- Distortion artifacts were decreased with the new trajectory.
- Signal-to-noise ratio was enhanced in both phantom and human brain images.
- Unipolar readout gradients eliminated ghost artifacts.
Conclusions:
- The modified cylindrical trajectory in 3D GRASE imaging effectively minimizes artifacts.
- This approach improves image quality for brain physiology studies.
- The technique offers a promising advancement in neuroimaging resolution and clarity.
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