Hyperpolarized Gas: Clinical Applications or No?
Edwin J.R. van Beek1

1Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom

Synopsis

Hyperpolarized gas MR imaging has shown promising results since its first evaluations began in the mid 1990s. However, after implementation of hyperpolarized 3-He MRI was showing of interest, conflicts with other fields requiring this gas made long-term application and translation impossible.

This has driven developments of 129-Xe MRI as an alternative, and following hardware, polarization and sequence changes, this method is now surging in applications and is being used for a variety of pathophysiological processes (that even go beyond the lung).

This presentation will highlight some of the latest developments and will offer a glimpse at the future of hyperpolarized 129-Xe MRI.

Body of Abstract

Hyperpolarized gas has been developed since the mid-1990s. Initially, 3-Helium was favoured due to its higher gyromagnetic ratio and therefore higher signal-to-noise (SNR). However, this method ran into difficulties as the availability of 3-Helium came under pressure as a result of competing areas of need, pushing up the price and reducing the ability to perform the necessary research. More recently, we have seen a resurgence of 129-Xenon as a method, which is more sustainable. The SNR issue has been addressed using higher levels of polarisation as well as improved imaging sequences. This has allowed further development and introduction of this method for studies in a wide field of lung diseases (including asthma, chronic obstructive pulmonary diseases, cystic fibrosis and interstitial lung diseases). Stricter methodological developments have created imaging-based quantifiable biomarkers, which can give direct information on regional lung function. These have been shown to correlate with disease severity and enable the study of therapeutic effectiveness. New insights can also be gained by studying the diffusion of 129-Xenon into the blood, and it is now even feasible to study this as a potential imaging modality to study the physiological interactions between lung function, lung perfusion, cardiac function and brain perfusion in a single investigation. In spite of the above developments, there is still not clear pathway to introducing the methodology into clinical practice. This is due to several factors, including costs of set-up, dedicated staff requirements and experience available in a limited number of centres. Nevertheless, as the technique is being incorporated in novel treatment trials, we can expect to see it make gradual headway into the translation into clinical practice. There is, however, still a long way to go!

Acknowledgements

I thank the support of SINAPSE (www.sinapse.ac.uk).

References

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Proc. Intl. Soc. Mag. Reson. Med. 26 (2018)