Extending the Lifetime of Hyperpolarized Propane Gas through Reversible Dissolution

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Hyperpolarization Techniques
• Biomedical Imaging Agents

Background:

• Hyperpolarized (HP) propane, produced via parahydrogen-induced polarization (PHIP), shows promise for functional lung MRI.
• A key limitation is its short gas-phase spin-lattice relaxation time (T1 < 1 s), hindering biomedical translation.
• Previous methods extended HP propane lifetime by ~3-fold using long-lived spin states.

Purpose of the Study:

• To investigate methods for significantly extending the hyperpolarization lifetime of propane.
• To assess the feasibility of using deuterated organic solvents to enhance HP propane stability.
• To determine if hyperpolarized propane can be recovered from solution to the gas phase while preserving polarization.

Main Methods:

• Hyperpolarized propane was produced using the PHIP technique.
• Propane was dissolved in deuterated organic solvents (acetone-d6 and methanol-d4) at high magnetic field (7.1 T).
• Hyperpolarization decay times (T1) were measured for dissolved propane; gas-phase recovery was also tested.

Main Results:

• Dissolving HP propane in deuterated solvents dramatically increased its hyperpolarization decay time.
• Decay times of 35.1 s (CH2) and 28.6 s (CH3) were observed in acetone-d6, ~50 times longer than gaseous propane.
• Similar extended lifetimes were achieved in methanol-d4.
• Successful retrieval of HP propane from solution to the gas phase with preserved hyperpolarization was demonstrated.

Conclusions:

• Dissolution in deuterated organic solvents is a highly effective strategy for extending HP propane lifetime at high magnetic fields.
• This approach significantly overcomes the translational challenge posed by short T1 relaxation times.
• The ability to recover HP propane from solution opens new avenues for its application in lung MRI and other biomedical imaging.