title: Oxygen-enhanced MRI of the lungs: intraindividual comparison between 1.5 and 3 tesla.
abstract: OBJECTIVE
  To assess the feasibility of oxygen-enhanced MRI of the lung at 3 Tesla and to compare signal characteristics with 1.5 Tesla.
  
  
  METHODS
  13 volunteers underwent oxygen-enhanced lung MRI at 1.5 and 3 T with a T 1-weighted single-slice non-selective inversion-recovery single-shot half-Fourier fast-spin-echo sequence with simultaneous respiratory and cardiac triggering in coronal orientation. 40 measurements were acquired during room air breathing and subsequently during oxygen breathing (15 L/min, close-fitting face-mask). The signal-to-noise ratio (SNR) of the lung tissue was determined with a difference image method. The image quality of all acquisitions was visually assessed. The mean values of the oxygen-induced relative signal enhancement and its regional coefficient of variation were calculated and the signal enhancement was displayed as color-coded parameter maps. Oxygen-enhancement maps were visually assessed with respect to the distribution and heterogeneity of the oxygen-related signal enhancement at both field strengths.
  
  
  RESULTS
  The mean relative signal enhancement due to oxygen breathing was 13 % (± 5.6 %) at 1.5 T and of 9.0 % (± 8.0 %) at 3 T. The regional coefficient of variation was significantly higher at 3 T. Visual and quantitative assessment of the enhancement maps showed considerably less homogeneous distribution of the signal enhancement at 3 T. The SNR was not significantly different but showed a trend to slightly higher values (increase of about 10 %) at 3 T.
  
  
  CONCLUSIONS
  Oxygen-enhanced pulmonary MRI is feasible at 3 Tesla. However, signal enhancement is currently more heterogeneous and slightly lower at 3 T.
authors.affiliation: Institut für Klinische Radiologie, Ludwig-Maximilians-Universität München, Klinikum Großhadern.
authors.forename: S F
authors.initials: SF
authors.lastname: Thieme
authors.forename: O
authors.initials: O
authors.lastname: Dietrich
authors.forename: D
authors.initials: D
authors.lastname: Maxien
authors.forename: K
authors.initials: K
authors.lastname: Nikolaou
authors.forename: S O
authors.initials: SO
authors.lastname: Schoenberg
authors.forename: M
authors.initials: M
authors.lastname: Reiser
authors.forename: C
authors.initials: C
authors.lastname: Fink
mesh_terms: D000328:Adult; D016477:Artifacts; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen; D010102:Oxygen Inhalation Therapy; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D012016:Reference Values; D012680:Sensitivity and Specificity; D012984:Software; D051598:Whole Body Imaging / Q000379:methods*; D055815:Young Adult
chemical_list: D010100:Oxygen