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Original Article
Using hyperpolarized 129Xe MRI to quantify regional gas transfer in idiopathic pulmonary fibrosis
  1. Jennifer M Wang1,
  2. Scott H Robertson2,3,
  3. Ziyi Wang2,4,
  4. Mu He2,5,
  5. Rohan S Virgincar2,4,
  6. Geoffry M Schrank2,
  7. Rose Marie Smigla6,
  8. Thomas G O’Riordan7,
  9. John Sundy7,
  10. Lukas Ebner8,9,
  11. Craig R Rackley6,
  12. Page McAdams9,
  13. Bastiaan Driehuys2,3,4,9
  1. 1School of Medicine, Duke University, Durham, North Carolina, USA
  2. 2Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina, USA
  3. 3Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA
  4. 4Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
  5. 5Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina, USA
  6. 6Department of Medicine, Division of Pulmonary, Allergy and Critical Care, Duke University Medical Center, Durham, North Carolina, USA
  7. 7Department of Respiratory Medicine, Gilead Sciences Inc, Foster City, California, USA
  8. 8Department of Radiology, University Hospital Inselspital, University of Bern, Bern, Switzerland
  9. 9Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA
  1. Correspondence to Bastiaan Driehuys, Department of Radiology, Duke University Medical Center, Center for In Vivo Microscopy Box 3302, Durham, NC 27710, USA; bastiaan.driehuys{at}duke.edu

Abstract

Background Assessing functional impairment, therapeutic response and disease progression in patients with idiopathic pulmonary fibrosis (IPF) continues to be challenging. Hyperpolarized 129Xe MRI can address this gap through its unique capability to image gas transfer three-dimensionally from airspaces to interstitial barrier tissues to red blood cells (RBCs). This must be validated by testing the degree to which it correlates with pulmonary function tests (PFTs) and CT scores, and its spatial distribution reflects known physiology and patterns of disease.

Methods 13 healthy individuals (33.6±15.7 years) and 12 patients with IPF (66.0±6.4 years) underwent 129Xe MRI to generate three-dimensional quantitative maps depicting the 129Xe ventilation distribution, its uptake in interstitial barrier tissues and its transfer to RBCs. For each map, mean values were correlated with PFTs and CT fibrosis scores, and their patterns were tested for the ability to depict functional gravitational gradients in healthy lung and to detect the known basal and peripheral predominance of disease in IPF.

Results 129Xe MRI depicted functional impairment in patients with IPF, whose mean barrier uptake increased by 188% compared with the healthy reference population. 129Xe MRI metrics correlated poorly and insignificantly with CT fibrosis scores but strongly with PFTs. Barrier uptake and RBC transfer both correlated significantly with diffusing capacity of the lungs for carbon monoxide (r=−0.75, p<0.01 and r=0.72, p<0.01), while their ratio (RBC/barrier) correlated most strongly (r=0.94, p<0.01). RBC transfer exhibited significant anterior-posterior gravitational gradients in healthy volunteers, but not in IPF, where it was significantly impaired in the basal (p=0.02) and subpleural (p<0.01) lung.

Conclusions Hyperpolarized129Xe MRI is a rapid and well-tolerated exam that provides region-specific quantification of interstitial barrier thickness and RBC transfer efficiency. With further development, it could become a robust tool for measuring disease progression and therapeutic response in patients with IPF, sensitively and non-invasively.

  • idiopathic pulmonary fibrosis
  • imaging/CT MRI etc
  • interstitial fibrosis

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Footnotes

  • Contributors CRR, PM and BD designed and implemented the study. JMW, SHR, ZW, MH, RSV, GMS and BD collected the data. JMW, SHR, ZW, MH and BD were responsible for data analysis. All authors contributed to the writing of the manuscript.

  • Funding Research reported in this publication was supported by the NIH/NHLBI R01HL105643 and R01HL126771, the Duke Center for In Vivo Microscopy, an NIH/NIBIB National Biomedical Technology Resource Center (P41 EB015897) and Gilead Sciences. LE received financial funding by the Swiss National Science Foundation.

  • Competing interests BD is founder and shareholder in Polarean Imaging, a company established to commercialise hyperpolarised 129Xe MRI technology.

  • Ethics approval This study was approved by the Duke Institutional Review Board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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