title: Multibreath alveolar oxygen tension imaging.
abstract: This study tested the ability of a multibreath hyperpolarized HP (3) He MRI protocol to increase the accuracy of regional alveolar oxygen tension (PA O2 ) measurements by lessening the influence of gas-flow artifacts. Conventional single-breath PA O2 measurement has been susceptible to error induced by intervoxel gas flow, particularly when used to study subjects with moderate-to-severe chronic obstructive pulmonary disease (COPD).
  
  
  
  Both single-breath and multibreath PA O2 imaging schemes were implemented in seven human subjects (one healthy, three asymptomatic smokers, and three COPD). The number and location of voxels with nonphysiologic PA O2 values generated by intervoxel gas flow were compared between the two protocols.
  
  
  
  The multibreath scheme resulted in a significantly lower total percentage of nonphysiologic PA O2 values (6.0%) than the single-breath scheme (13.7%) (P = 0.006). PA O2 maps showed several patterns of gas-flow artifacts that were present in the single-breath protocol but mitigated by the multibreath approach. Multibreath imaging also allowed for the analysis of slow-filling areas that presented no signal after a single breath.
  
  
  
  A multibreath approach enhances the accuracy and completeness of noninvasive PA O2 measurement by significantly lessening the proportion of nonphysiologic values generated by intervoxel gas flow. Magn Reson Med 76:1092-1101, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Clapp
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Hooman
authors.initials: H
authors.lastname: Hamedani
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Kadlecek
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xin
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Hoora
authors.initials: H
authors.lastname: Shaghaghi
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Sarmad
authors.initials: S
authors.lastname: Siddiqui
authors.affiliation: Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Milton D
authors.initials: MD
authors.lastname: Rossman
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA. rahim.rizi@uphs.upenn.edu.
authors.forename: Rahim R
authors.initials: RR
authors.lastname: Rizi
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D006371:Helium / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006801:Humans; D007554:Isotopes / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D011650:Pulmonary Alveoli / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000379:methods; D015656:Respiratory Mechanics / Q000502:physiology*; D012680:Sensitivity and Specificity
chemical_list: D007554:Isotopes; D019275:Radiopharmaceuticals; D006371:Helium; C000615206:Helium-3; D010100:Oxygen
keywords: COPD; air trapping; alveolar oxygen tension; collateral ventilation; diffusion; hyperpolarized magnetic resonance imaging; multibreath; slow filling; smoking