Concentric rings K-space trajectory for hyperpolarized (13)C MR spectroscopic imaging

Area of Science:

• Magnetic Resonance Imaging
• Spectroscopic Imaging
• Medical Physics

Background:

• Hyperpolarized Carbon-13 (HP ¹³C) MR Spectroscopic Imaging (MRSI) enables real-time metabolic imaging.
• Current MRSI techniques face limitations in speed and efficiency, hindering clinical translation.
• Rapid acquisition is crucial for capturing dynamic metabolic processes with HP ¹³C MRSI.

Purpose of the Study:

• To develop and evaluate a novel concentric rings readout trajectory for HP ¹³C MRSI.
• To assess the performance and feasibility of this technique in phantom and in vivo studies.
• To investigate the benefits of parallel imaging acceleration with the concentric rings trajectory.

Main Methods:

• A concentric rings readout trajectory with constant angular velocity was designed and analyzed.
• Quantitative tradeoffs were evaluated for various imaging scenarios.
• The technique was applied to ¹³C phantoms and in vivo animal HP ¹³C MRSI studies.
• Parallel imaging acceleration was implemented and assessed.

Main Results:

• The concentric rings trajectory offers significant acquisition time savings compared to echo-planar spectroscopic imaging (EPSI).
• It provides sufficient spectral bandwidth and high efficiency, outperforming EPSI and spiral techniques.
• Phantom and in vivo studies demonstrated good image quality, reduced scan times, and fewer artifacts than EPSI.
• Parallel imaging accelerated concentric rings showed improved g-factor performance and aliasing-free results in vivo.

Conclusions:

• The concentric rings trajectory is a robust and rapid imaging method for HP ¹³C MRSI.
• It meets the speed, bandwidth, and resolution requirements for advanced metabolic imaging.
• This technique shows great promise for accelerating HP ¹³C MRSI acquisition and improving image quality.