Accelerated fractional ventilation imaging with hyperpolarized Gas MRI

Kiarash Emami, Yinan Xu, Hooman Hamedani, Harrilla Profka, Stephen Kadlecek, Yi Xin, Masaru Ishii, Rahim R. Rizi

Research output: Contribution to journalArticle


Purpose To investigate the utility of accelerated imaging to enhance multibreath fractional ventilation (r) measurement accuracy using hyperpolarized gas MRI. Undersampling shortens the breath-hold time, thereby reducing the O2-induced signal decay and allows subjects to maintain a more physiologically relevant breathing pattern. Additionally, it may improve r estimation accuracy by reducing radiofrequency destruction of hyperpolarized gas. Methods Image acceleration was achieved using an eight-channel phased array coil. Undersampled image acquisition was simulated in a series of ventilation images and data was reconstructed for various matrix sizes (48-128) using generalized auto-calibrating partially parallel acquisition. Parallel accelerated r imaging was also performed on five mechanically ventilated pigs. Results Optimal acceleration factor was fairly invariable (2.0-2.2×) over the range of simulated resolutions. Estimation accuracy progressively improved with higher resolutions (39-51% error reduction). In vivo r values were not significantly different between the two methods: 0.27 ± 0.09, 0.35 ± 0.06, 0.40 ± 0.04 (standard) versus 0.23 ± 0.05, 0.34 ± 0.03, 0.37 ± 0.02 (accelerated); for anterior, medial, and posterior slices, respectively, whereas the corresponding vertical r gradients were significant (P <0.001): 0.021 ± 0.007 (standard) versus 0.019 ± 0.005 (accelerated) (cm-1). Conclusion Quadruple phased array coil simulations resulted in an optimal acceleration factor of ∼2× independent of imaging resolution. Results advocate undersampled image acceleration to improve accuracy of fractional ventilation measurement with hyperpolarized gas MRI. Magn Reson Med 70:1353-1359, 2013. © 2013 Wiley Periodicals, Inc.

Original languageEnglish (US)
Pages (from-to)1353-1359
Number of pages7
JournalMagnetic Resonance in Medicine
Issue number5
Publication statusPublished - Nov 2013



  • accelerated ventilation imaging
  • fractional ventilation
  • generalized auto-calibrating partially parallel acquisition
  • hyperpolarized gas MRI
  • mechanical ventilation
  • parallel MRI
  • pulmonary ventilation
  • quantitative lung imaging

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

Emami, K., Xu, Y., Hamedani, H., Profka, H., Kadlecek, S., Xin, Y., ... Rizi, R. R. (2013). Accelerated fractional ventilation imaging with hyperpolarized Gas MRI. Magnetic Resonance in Medicine, 70(5), 1353-1359.