Hyperpolarized Gas Imaging

Thursday 15 May 2014

Stanley J Kruger¹, Scott K Nagle^1,2, Robert V Cadman¹, Kevin M Johnson^1,2, Laura C Bell¹, Andrew D Hahn¹, and Sean B Fain^1,2
1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, ²Radiology, University of Wisconsin - Madison, Madison, WI, United States

Oxygen Enhanced MRI with 3D radial ultrashort echo time (OE-MRI) is an emerging technique for the evaluation of lung ventilation with advantages over hyperpolarized noble gas MRI (HP-MRI) in terms of accessibility and cost effectiveness. Nonetheless, HP-MRI is an emerging reference standard for pulmonary MRI of ventilation. The purpose of this work is to compare the heterogeneity of ventilation as depicted regionally for the same subjects with HP-MRI and OE-MRI to evaluate regional distribution of ventilation defects using the respective techniques. The whole-lung coverage provided by 3D radial OE-MRI could be readily compared to HP-MRI as a reference standard.

Andreas Voskrebenzev¹, Marcel Gutberlet¹, Lena Becker¹, Julius Renne¹, Jan Hinrichs¹, Christian Schönfeld¹, Sajoscha Sorrentino¹, Frank Wacker¹, and Jens Vogel-Claussen^1
1Radiology, Medical School Hannover, Hannover, Lower Saxony, Germany

Fourier Decomposition (FD) is a method to calculate ventilation-weighted images of the lung without the need of any contrast agent. These images can be used to determine the dimensionless specific ventilation (SV). We introduce the global SV as the ratio of breathing volume change to lung volume during mid-position of respiration. The presented correlation of global and FD SV could be utilized to normalize the SV maps in cross-sectional and longitudinal studies. Thereby, this study shows that the combination of MRI and real-time respiration detection is of relevance for the comparison of absolute SV values.

Sarah Svenningsen^1,2, Gregory Paulin^1,2, Miranda Kirby^1,2, Nikhil Kanhere^1,3, Roya Etemad-Rezai⁴, David G McCormack⁵, and Grace Parraga^1,2
1Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada, ²Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada, ³Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada,⁴Department of Medical Imaging, The University of Western Ontario, London, Ontario, Canada, ⁵Department of Medicine, The University of Western Ontario, London, Ontario, Canada

In subjects with advanced COPD, we evaluated hyperpolarized ³He MRI measurements of emphysema and airways disease in a study of the 4-week treatment efficacy of a handheld airway clearance device for mobilizing mucous secretions. Whereas all subjects reported a modest improvement in ease of clearing mucous following therapy, 6/14 subjects showed improved ³He MRI ventilation (p=0.04), with concomitantly improved forced vital capacity and 6MWD, and this was not observed in imaging non-responders. In addition, imaging measurements of emphysema was a negative-predictor of response. Non-invasive imaging measurements of COPD can be used as intermediate endpoints and phenotypes in therapy trials.

He N. Xu^1,2, Hoora Shaghaghi¹, Stephen Kadlececk¹, Harrilla Profka¹, Lin Z. Li^1,2, and Rahim Rizi^1
1Radiology Department, University of Pennsylvania, Philadelphia, PA, United States, ²Britton Chance Lab of Redox Imaging, Johnson Research Foundation, University of Pennsylvania, Philadelphia, PA, United States

A non-invasive method for assessing lung injury is needed. We aimed to identify an early metabolic predictor of lung inflammation using the hyperpolarized 13C-NMR technique. Rat lung injury was induced by bleomycin and studied by injecting hyperpolarized 13C-pyruvate to the perfused lung 7 and 21 days after the treatment. The larger rate constants of the LDH-catalyzed reaction quantified by the ratiometric analysis of the time course of lactate/pyruvate ratio indicate inflammation sped up both the forward and reverse reaction rates and altered the cellular redox state. Our results indicate that HP-13C-NMR data can be useful for probing lung disorders.

Kun Qing¹, Kai Ruppert^1,2, Tally A. Altes¹, Yun Jiang³, Jaime F. Mata¹, G. Wilson Miller¹, Yang Yang¹, Yun M. Shim¹, Steven Guan¹, Iulian C. Ruset^4,5, F. William Hersman^4,5, and John P. Mugler^1
1University of Virginia, Charlottesville, VA, United States, ²Cincinnati Children's Hospital, Cincinnati, OH, United States, ³Case Western Reserve University, Cleveland, OH, United States, ⁴Xemed LLC, Durham, NH, United States, ⁵University of New Hampshire, Durham, NH, United States

For this study, we used 3-D Xe-129 dissolved-phase imaging method to investigate functional changes in the lungs of 10 asthmatics, as compared to 12 healthy subjects. The relatively high RBC-to-tissue ratios, low tissue-to-gas ratios, and normal ADC values found in 7 asthmatics represent a unique combination that has not been seen in healthy or COPD subjects. These values may be associated with airway inflammation and remodeling of both the airways and vasculature. All ratios were low in two older asthmatics, indicating impaired gas exchange possibly due to emphysematous tissue destruction and thickening of alveolar walls, similar to COPD.

Neil James Stewart¹, General Leung¹, Graham Norquay¹, Helen Marshall¹, Juan Parra-Robles¹, Andy Swift¹, Jan Wolber^1,2, Rolf Schulte³, Nehal Hussain⁴, Robin Condliffe⁴, Charlie Elliot⁴, Philip Murphy⁵, Moira Whyte⁴, David Kiely⁴, and Jim Michael Wild^1
1Academic Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom, ²GE Healthcare, Amersham, Buckinghamshire, United Kingdom,³GE Global Research, Garching, Bavaria, Germany, ⁴Respiratory Medicine, University of Sheffield, Sheffield, South Yorkshire, United Kingdom,⁵GlaxoSmithKline, Southall, Greater London, United Kingdom

In this work, hyperpolarised 129Xe was assessed as a functional tool for the study of gas exchange in the human lungs. The Chemical Shift Saturation Recovery technique was utilised to quantify changes in lung microstructure and consequent degradation of lung function in subjects with idiopathic pulmonary fibrosis and systemic sclerosis, via non-invasive measurement of septal thickening and elevated pulmonary-capillary transit times. The results of this study correlated well with dynamic contrast enhanced MRI and hyperpolarised 3He diffusion MRI.

Mu He¹, Suryanarayanan Sivaram Kaushik^1,2, Scott Haile Robertson^1,3, Matthew S Freeman^1,3, Rohan S Virgincar^1,2, Holman Page McAdams⁴, Denise Beaver⁵, Monica Kraft⁵, and Bastiaan Driehuys^1,2
1Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States, ²Department of Biomedical Engineering, Duke University, Durham, NC, United States, ³Medical Physics Graduate Program, Duke University, Durham, NC, United States, ⁴Department of Radiology, Duke University Medical Center, Durham, NC, United States, ⁵Department of Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, NC, United States

Asthma treatment is generally less effective for older patients. Yet, most published studies exclude subjects aged over 65 years-of-age to avoid expected confounding effects from other coexisting obstructive lung disorders. In this work, hyperpolarized ¹²⁹Xe MRI was used to acquire ventilation images in younger and older asthmatics, as well as healthy controls matched for body mass, ethnicity, and age. To quantify differences between groups, test for short-term image reproducibility and evaluate bronchodilator response, we introduce an improved semi-automated cluster analysis method to calculate ventilation defect percentage (VDP).

Marcus J. Couch^1,2, Iain K. Ball², Tao Li², Matthew S. Fox², Alexei V. Ouriadov², Birubi Biman^3,4, and Mitchell S. Albert^1,2
1Lakehead University, Thunder Bay, Ontario, Canada, ²Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada, ³Thunder Bay Regional Health Sciences Centre, Thunder Bay, Ontario, Canada, ⁴Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada

¹⁹F MRI of the lungs is a new pulmonary imaging modality that uses inhaled inert fluorinated gases as a signal source to acquire images of the lungs. The purpose of this study was to investigate optimized image acquisition strategies by optimizing and comparing UTE and gradient echo images in both a resolution phantom and healthy volunteers. Overall, UTE lung images had a higher SNR than gradient echo images, but also had poorer edge definition. On the other hand, gradient echo images had a lower SNR than UTE, but showed more edge detail and had a higher resolving power.

Le Zhang¹, Rosa Tamara Branca^2,3, Ting He², and Camille Ehre^4
1Curriculum in Applied Science and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, ²Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, ³Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, ⁴Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

A combination of ultrashort echo time proton imaging technique and hyperpolarized 129Xenon MRI was presented to detect mucus accumulation inside lungs of mice with cystic fibrosis symptoms. Histology was also performed to validate the findings.

Alexander L Sukstanskii¹, James D Quirk¹, and Dmitriy A Yablonskiy^1
1Radiology, Washington University, St. Louis, Missouri, United States

A new approach – Gradient Echo Plural Contrast Imaging (GEPCI) of lungs – is proposed for simultaneously extracting information about lung ventilation, alveolar parameters and blood vessel network structure from a single multi-gradient-echo experiment. Based on computer simulations of 3He atoms diffusion in the acinar airway tree in the presence of inhomogeneous magnetic field induced by the susceptibility differences between lung tissue (alveolar septa, blood vessels) and lung airspaces, we derive analytical expressions relating the time-dependent MR signal to the geometrical parameters of acinar airways and blood vessel network. Data obtained on 8 healthy volunteers are in good agreement with literature values.