Lung diseases have become a major public health problem in China, with the number of patients rising in recent years due to smoking, air pollution and an aging population.

Imaging technologies currently in use, including Computed Tomography (CT) and Positron Emission Tomography (PET) scans, are far from perfect.

On the one hand, those technologies pose health risks. On the other hand, both CT and PET scans fail to provide essential indicators for measuring gas and gas-blood exchanges in the lungs to assess lung health comprehensively.

Traditional Magnetic Resonance Imaging (MRI), though radiation-free, is unavailable for the human lung, since the technology relies on water proton signals. The lung mainly contains gases and cavities, with the density of water protons being approximately 1,000 times lower than normal tissues of the human body. 

In order to “light up” the lung, gas signals need to be enhanced by tens of thousands of folds. Currently, non-invasive, radiation-free clinical imaging devices that are capable of monitoring gas exchanges in the lung are not available on the market, which significantly hinders in-depth research on major lung diseases. 

A research team led by PhD Zhou Xin from the Wuhan Institute of Physics and Mathematics under the Chinese Academy of Sciences (CAS) has pioneered a study on lung MRI using hyperpolarized gases.

The new technology marks a breakthrough in using MRI for early detection of lung diseases. The hyperpolarized noble gas, 129Xe, is safe, non-toxic, fat-soluble and chemical-shift-sensitive, with unique advantages in detecting exchanges of gases and blood in the lungs.

With financial support from the National Natural Science Foundation of China and the CAS, the researchers have successfully developed a highly productive, automatic, and portable 129Xe gas hyperpolarization device, which is capable of boosting enhancement of nuclear spin polarization to more than 44,000 folds.

A vest-like highly-sensitive lung imaging probe developed by the team possesses a good homogeneity for transmitting and receiving magnetic resonance signals.

The researchers have also proposed a CEIT（Chemical Exchange Inversion Transfer） sequence, which can capture dynamics and imaging information about O₂-CO₂ exchanges, along with blood-O₂ exchanges, in an efficient, quantitative approach.

These findings have been published on Magnetic Resonance in Medicine and endorsed by international experts.

Recently, the researchers joined hands with a team headed by Wu Guangyao at the Zhongnan Hospital of Wuhan University, and got the very first hyperpolarized gas lung image of an asthma patient in China.

Compared with traditional CT exams, the new technology can diagnose ventilatory defects in a non-invasive, radiation-free and visualized approach, a brand-new method for early detection of lung diseases.

Conventional proton MRI of human lung (L) and the first hyperpolarized 129Xe lung image of an asthma patient in China (R).

Professor Zhou Xin (R) and Dr. Wu Guangyao (L) discuss the hyperpolarized lung image of a volunteer at the laboratory of Wuhan Institute of Physics and Mathematics, CAS, on Sept 6. (Photo by Jin Liwang / Xinhua)