Polarised Imaging Systems

Polariser Physics

Polariser physics

We have in house experience of design and construction of polarisers for hyperpolarisation of 3He and 129Xe gases for lung MRI using high power frequency-narrowed lasers. The research has focused on understanding the spin exchange optical pumping physics for generation of highly polarized 129Xe for supply-on-demand clinical lung imaging. Our systems have been taken through the regulatory licencing process with the MHRA for administration of both gases as lung imaging contrast agents. POLARIS can provide research support with third party contract collaborations on the polarizer hardware and regulatory aspects.

Key Recent Publications:

Norquay G, Parnell SR, Xu X, Parra-Robles J, Wild JM. Optimized production of hyperpolarized 129Xe at 2 bars for in vivo lung magnetic resonance imaging. Journal of Applied Physics, 113. Published online January 2013. doi

Parnell SR, Deppe MH, Parra-Robles J, Wild JM. Enhancement of 129Xe polarization by off-resonant spin exchange optical pumping. Journal of Applied Physics, 2010, 108(6). doi

Image Processing and Computational Modelling

Image processing and computational modelling

We develop novel image processing methods for image quantification to extract quantitative indices of regional pulmonary function. We are also using imaging data as a basis of multi-scale computational models of gas flow and diffusion in the lungs as non-invasive estimators of lung micro structure-function. This work is being used as a basis for personalized models of lung disease in the Virtual Physiological Human project AIRProm.

Key Recent Publications:

Parra-Robles J, Wild JM. The influence of lung airways branching structure and diffusion time on measurements and models of short-range 3He gas MR diffusion. Journal of Magnetic Resonance, 2012, 225:102-13. doi

Parra-Robles J, Ajraoui S, Deppe MH, Parnell SR, Wild JM. Experimental investigation and numerical simulation of 3He gas diffusion in simple geometries: implications for analytical models of 3He MR lung morphometry. Journal of Magnetic Resonance, 2010, 204(2), 228-238. doi

Burrowes KS, De Backer J, Smallwood R, Sterk PJ, Gut I, Wirix-Speetjens R, Siddiqui S, Owers-Bradley J, Wild JM, Maier D, Brightling C, and the AirPROM Consortium. Multi-scale computational models of the airways to unravel the pathophysiological mechanisms in asthma and chronic obstructive pulmonary disease (AirPROM). Interface Focus 2013 3:20120057. doi

Custom RF Coil Designs

Custom RF coil designs

We have a dedicated RF engineering lab for coil hardware engineering and we work on novel transmitter and receiver array designs for 1H ,3He and 129Xe lung, abdominal and brain MRI. We have explored the theoretical and experimental RF sensitivity of HP gas MRI at different magnetic field strengths. POLARIS can provide custom RF engineering for research collaborators through contract work and we work closely with industry in the area of RF coils eg GE Healthcare, Clinical MR Solutions, Rapid Biomedical and Pulseteq.

Key Recent Publications:

Deppe MH, Parra-Robles J, Marshall H, Lanz T, Wild JM. A flexible 32-channel receive array combined with a homogeneous transmit coil for human lung imaging with hyperpolarized 3He at 1.5 T. Magnetic Resonance in Medicine, 2011; 66: 1788-1797. doi

De Zanche N, Chhina N, Teh K, Randell C, Pruessmann KP, Wild JM. Asymmetric quadrature split birdcage coil for hyperpolarized 3He lung MRI at 1.5T. Magnetic Resonance in Medicine, 2008; 60(2):431-8. doi

Xu X, Norquay G, Parnell SR, Deppe MH, Ajraoui S, Hashoian R. Wild JM. Hyperpolarized 129Xe gas lung MRI-SNR and T2* comparisons at 1.5 T and 3 T. Magnetic Resonance in Medicine, 2012; 68(6):1900-1904. doi

Innovative MR Acquisition Strategies for Multinuclear Lung MR

Innovative MR acquisition strategies for multinuclear lung MRWe have a world leading track record in the development of MR sequences for rapid functional imaging of inhaled hyperpolarised gases in the lungs. Using non Cartesian sampling, compressed sensing, steady state free precession and parallel imaging we have pushed the sensitivity of the methods and opened up sensitivity to new aspects of lung physiology. In recent work we have developed methods for simultaneous imaging of 1H, 3He and 129Xe in the lungs maximizing the structure and functional information attainable.

Key Recent Publications:

Wild JM, Marshall H, Xu X, Norquay G, Parnell SR, Clemence M, Griffiths PD, Parra-Robles J. Simultaneous imaging of lung structure and function with triple-nuclear hybrid MR imaging. Radiology, 2013; 267(1):251-5. doi

Ajraoui S, Parra-Robles J, Wild JM. Incorporation of prior knowledge in compressed sensing for faster acquisition of hyperpolarized gas images. Magnetic Resonance in Medicine, 2013;69(2):360-9. doi

Deppe MH, Wild JM. Variable flip angle schedules in bSSFP imaging of hyperpolarized noble gases. Magnetic Resonance in Medicine, 2012;67(6):1656-64. doi