March 25, 2016 - The use of specially–treated krypton gas as an inhalable contrast agent to make the spaces inside the lungs show up on a magnetic resonance imaging (MRI) scan could enable space inside the lungs to be visible on an MRI, according to a study published in Proceedings of the National Academy of Sciences.¹

Recent technological developments have led to a novel imaging methodology called inhaled hyperpolarized gas MRI that uses lasers to 'hyperpolarize' a noble (inert) gas, which aligns (polarizes) the nuclei of the gas so it shows up on an MRI scan. The work will make 3D imaging using 'atomic spies' like helium, xenon, or krypton possible in a single breath hold by the patient. In the new paper, researchers have developed a technique to generate hyperpolarized krypton gas at high purity, a step that will significantly facilitate the use of this new contrast agent for pulmonary MRI.

Traditional MRI uses hydrogen protons in the body as molecular targets to generate a picture of tissue does not give as detailed a picture of the lungs because they are full of air. The work will make 3D imaging using 'atomic spies' like helium, xenon, or krypton possible in a single breath hold by the patient. Nottingham has pioneered hyperpolarized krypton MRI and is currently advancing this technology towards the clinical approval processes.

Legend: Recent technological developments have led to a novel imaging methodology called Inhaled Hyperpolarized Gas MRI.²  

Hyperpolarized MRI research has been trying to overcome a problem with these noble gases retaining their hyperpolarized state for long enough for the gas to be inhaled, held in the lungs and scanned. Now in a paper published in the Proceedings of the National Academy of Sciences, the Nottingham team has developed a new technique to generate hyperpolarized krypton gas at high purity, a step that will significantly facilitate the use of this new contrast agent for pulmonary MRI.

Chair in Translational Imaging at the Sir Peter Mansfield Imaging Centre, Professor Thomas Meersmann, said: "It is particularly demanding to retain the hyperpolarized state of krypton during preparation of this contrast agent. We have solved a problem by using a process that is usually associated with clean energy related sciences. It's called catalytic hydrogen combustion. To hyperpolarize the krypton-83 gas we diluted it in molecular hydrogen gas for the laser pumping process. After successful laser treatment the hydrogen gas is mixed with molecular oxygen and literally exploded it away in a safe and controlled fashion through a catalyzed combustion reaction.

"Remarkably, the hyperpolarized state of krypton-83 'survives' the combustion event. Water vapor, the sole product of the 'clean' hydrogen reaction, is easily removed through condensation, leaving behind the purified laser-polarized krypton-83 gas diluted only by small remaining quantities of harmless water vapor. This development significantly improves the potential usefulness of laser-pumped krypton-83 as MRI contrast agent for clinical applications."

 

References:

1. Nicola J. Rogers, Fraser Hill-Casey, Karl F. Stupic, Joseph S. Six, Clémentine Lesbats, Sean P. Rigby, Jacques Fraissard, Galina E. Pavlovskaya, Thomas Meersmann. Molecular hydrogen and catalytic combustion in the production of hyperpolarized83Kr and129Xe MRI contrast agents. Proceedings of the National Academy of Sciences, 2016; 201600379 DOI: 10.1073/pnas.1600379113.

2. Major Breakthrough in MRI Scan Technology for Lung Disease. www.mpo-mag.com. University of Nottingham.  March 10, 2016. http://www.mpo-mag.com/contents/view_breaking-news/2016-03-10/major-breakthrough-in-mri-scan-technology-for-lung-disease#sthash.038KQX8P.dpuf