Developing Hyperpolarized Butane Gas for Ventilation Lung Imaging.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging Physics
• Hyperpolarized Contrast Agents

Background:

• NMR hyperpolarization significantly enhances MRI sensitivity, enabling new applications like gas imaging.
• Hyperpolarized 129Xe is FDA-approved for lung imaging but faces challenges in production cost and scanner compatibility.
• Proton-hyperpolarized propane showed promise but suffered from rapid signal decay and slow production rates.

Purpose of the Study:

• To investigate high-capacity production of hyperpolarized butane gas.
• To assess the stability and production speed of hyperpolarized butane.
• To demonstrate the feasibility of hyperpolarized butane for lung ventilation imaging.

Main Methods:

• Utilized heterogeneous parahydrogen-induced polarization with Rh nanoparticle catalysts.
• Employed butene gas as a precursor for pairwise addition of parahydrogen.
• Evaluated hyperpolarized butane's spin-state lifetime (T1 and TS) and production rates.
• Performed phantom and excised lung imaging using clinical MRI scanners.

Main Results:

• Achieved a doubled hyperpolarized state lifetime for butane (T1 ~1.6 s, TS ~3.8 s at 1 bar) compared to propane.
• Demonstrated a high production speed of up to 0.7 standard liters per second.
• Successfully imaged hyperpolarized butane in phantoms and excised rabbit lungs with high resolution (1.6 x 1.6 mm²).

Conclusions:

• Hyperpolarized butane offers a promising, stable, and rapidly produced proton-based contrast agent for MRI.
• This technology circumvents limitations of 129Xe, enabling wider clinical use of functional lung imaging.
• The development paves the way for cost-effective, on-demand production and imaging on various MRI systems, including low-field scanners.