title: Volumetric MRI of the lungs during forced expiration.
abstract: Lung function is typically characterized by spirometer measurements, which do not offer spatially specific information. Imaging during exhalation provides spatial information but is challenging due to large movement over a short time. The purpose of this work is to provide a solution to lung imaging during forced expiration using accelerated magnetic resonance imaging. The method uses radial golden angle stack-of-stars gradient echo acquisition and compressed sensing reconstruction.
  
  
  
  A technique for dynamic three-dimensional imaging of the lungs from highly undersampled data is developed and tested on six subjects. This method takes advantage of image sparsity, both spatially and temporally, including the use of reference frames called bookends. Sparsity, with respect to total variation, and residual from the bookends, enables reconstruction from an extremely limited amount of data.
  
  
  
  Dynamic three-dimensional images can be captured at sub-150 ms temporal resolution, using only three (or less) acquired radial lines per slice per timepoint. The images have a spatial resolution of 4.6×4.6×10 mm. Lung volume calculations based on image segmentation are compared to those from simultaneously acquired spirometer measurements.
  
  
  
  Dynamic lung imaging during forced expiration is made possible by compressed sensing accelerated dynamic three-dimensional radial magnetic resonance imaging. Magn Reson Med 75:2295-2302, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Program in Applied Mathematics, University of Arizona, Tucson, Arizona, USA.
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Berman
authors.affiliation: Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona, USA.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Pandey
authors.affiliation: Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona, USA.
authors.forename: Zhitao
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA.
authors.forename: Lindsie
authors.initials: L
authors.lastname: Jeffries
authors.affiliation: Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA.|Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Trouard
authors.affiliation: Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.
authors.forename: Isabel
authors.initials: I
authors.lastname: Oliva
authors.affiliation: Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.
authors.forename: Felipe
authors.initials: F
authors.lastname: Cortopassi
authors.affiliation: Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.
authors.forename: Diego R
authors.initials: DR
authors.lastname: Martin
authors.affiliation: Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.
authors.forename: Maria I
authors.initials: MI
authors.lastname: Altbach
authors.affiliation: Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona, USA.|Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA.|Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Bilgin
mesh_terms: D045853:Exhalation / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging* / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D013147:Spirometry / Q000379:methods*
keywords: compressed sensing; forced expiration; pulmonary; spirometry