Nuclear magnetic resonance imaging with hyperpolarised helium-3

Area of Science:

• Medical Imaging
• Pulmonology
• Nuclear Magnetic Resonance

Background:

• Traditional Magnetic Resonance Imaging (MRI) is limited in imaging low proton-content tissues like lungs due to reliance on water molecule signals.
• Imaging lung air spaces is challenging with conventional MRI techniques.
• Spin-polarized helium-3 (3He) offers a novel approach for lung imaging.

Purpose of the Study:

• To investigate the feasibility of using hyperpolarized helium-3 (3He) for Magnetic Resonance Imaging (MRI) of the lungs.
• To assess the potential of 3He MRI as an alternative to existing nuclear medicine imaging methods for pulmonary diagnostics.

Main Methods:

• A volunteer inhaled hyperpolarized 3He gas to fill the lungs.
• Conventional MRI detector assembly was used to image the lungs.
• Laser optical pumping significantly enhanced the nuclear spin polarization of 3He, overcoming signal loss due to lower gas density.

Main Results:

• In-vivo MRI successfully visualized the lungs using hyperpolarized 3He.
• The 3He MRI clearly delineated lung air spaces from surrounding structures like the diaphragm, heart, and chest wall.
• Signal intensity correlated with regional lung ventilation, showing stronger signals in well-ventilated areas and weaker signals in less ventilated regions.

Conclusions:

• Hyperpolarized 3He MRI is a viable alternative to current nuclear medicine techniques for lung imaging.
• This method enables direct visualization of pulmonary air spaces, facilitating the study of ventilation.
• 3He MRI offers potential for investigating physiological and pathophysiological processes related to regional lung ventilation distribution.