Three-frequency RF coil designed for optimized imaging of hyperpolarized, 13C-labeled compounds

Area of Science:

• Magnetic Resonance Imaging
• Biophysics
• Medical Physics

Background:

• Hyperpolarized (13)C-labeled compounds require specialized radiofrequency (RF) coils for efficient signal detection in Magnetic Resonance Imaging (MRI).
• Standard MRI protocols necessitate different RF frequencies for various stages, including anatomical localization, shimming, and hyperpolarized compound imaging.
• Flip angle (FA) calibration is crucial for quantitative imaging but challenging at the (13)C frequency, while the naturally abundant (23)Na signal offers a viable alternative for this step.

Purpose of the Study:

• To develop a single RF coil capable of operating at multiple frequencies for hyperpolarized (13)C MRI.
• To enable efficient signal utilization across different stages of the MRI examination, from setup to image acquisition.
• To demonstrate the feasibility of using a single resonant structure for (1)H, (23)Na, and (13)C frequencies.

Main Methods:

• Design and construction of a novel RF resonant structure.
• Characterization of the RF coil's linear operation at (1)H and (23)Na frequencies for scan setup.
• Evaluation of the RF coil's quadrature operation at the (13)C frequency for imaging.
• In vivo imaging experiments using hyperpolarized (13)C compounds.

Main Results:

• A single RF coil was successfully developed, demonstrating linear operation at (1)H and (23)Na frequencies and quadrature operation at the (13)C frequency.
• The coil facilitated accurate anatomical localization and shimming using the (1)H frequency.
• Flip angle calibration was effectively performed using the natural abundance (23)Na signal.
• In vivo images of hyperpolarized (13)C compounds were acquired using the developed RF coil.

Conclusions:

• A versatile, single RF coil can effectively support multiple frequencies required for hyperpolarized (13)C MRI examinations.
• This multi-resonant coil design simplifies scan setup and improves quantitative accuracy by enabling FA calibration at the (23)Na frequency.
• The developed RF coil shows significant potential for advancing in vivo hyperpolarized (13)C MRI techniques.