Simultaneous multiagent hyperpolarized (13)C perfusion imaging.

Area of Science:

• Magnetic Resonance Imaging
• Molecular Imaging
• Biomedical Engineering

Background:

• Current perfusion MRI techniques face limitations in simultaneously assessing multiple physiological parameters.
• Developing novel contrast agents and imaging sequences is crucial for advancing molecular imaging capabilities.

Purpose of the Study:

• To demonstrate simultaneous hyperpolarization and imaging of three distinct (13)C-labeled perfusion MRI contrast agents.
• To exploit the varying diffusibility of these agents for simultaneous measurement of vascular permeability and perfusion.
• To apply these novel methods in initial preclinical studies.

Main Methods:

• A novel pulse sequence was developed for rapid, dynamic multislice imaging using balanced steady-state free precession excitation and spectral-spatial readout.
• Multiband frequency encoding was employed to accommodate the distinct chemical shifts of the agents.
• Perfusion modeling methods were utilized to quantify vascular permeability and perfusion parameters based on tracer bilayer permeability.

Main Results:

• Dynamic imaging successfully differentiated the distribution patterns of the individual (13)C-labeled tracers.
• Computed permeability maps revealed differential permeability across brain tissues.
• Elevated tumor perfusion and permeability were observed in preclinical models compared to normal tissues.

Conclusions:

• Tripolarized perfusion MRI offers a novel approach for simultaneous in vivo monitoring of permeability, perfusion, and transport.
• This technique provides new molecular imaging measures for enhanced preclinical research.
• The study successfully demonstrated the feasibility of simultaneous imaging of multiple (13)C agents with varying properties.