title: Asthma: comparison of dynamic oxygen-enhanced MR imaging and quantitative thin-section CT for evaluation of clinical treatment.
abstract: OBJECTIVE
  To compare the use of dynamic oxygen-enhanced magnetic resonance (MR) imaging with the use of quantitatively assessed computed tomography (CT) for assessment of clinical stage and evaluation of pulmonary functional change due to treatment in patients with asthma.
  
  
  METHODS
  The institutional review board of Kobe University Hospital approved this study, and written informed consent was obtained from each subject. Thirty consecutive patients with asthma (17 men and 13 women; age range, 27-78 years) underwent dynamic oxygen-enhanced MR imaging, multidetector CT, and assessment of forced expiratory volume in 1 second. All patients were classified as having one of four stages of asthma according to the guidelines of the National Asthma Education and Prevention Program. Relative enhancement ratio ( RER relative enhancement ratio ) and wash-in time maps were generated by means of pixel-by-pixel analyses. Regions of interest were placed on images of the lung in all sections, and all measurements were averaged to determine mean RER relative enhancement ratio and mean wash-in time for each subject. Percentage of airway wall area and mean lung density were determined at quantitative CT. For comparison of the modalities for assessment of clinical stage, indexes of subjects at all clinical stages were compared by means of the Tukey honestly significant difference test. Evaluation of pulmonary functional improvement was assessed by correlating improvement of each index with that of forced expiratory volume.
  
  
  RESULTS
  Mean wash-in time was significantly different among patients with asthma of different clinical stages (P < .05), but significant differences between mean RER relative enhancement ratio and percentage of airway wall area were observed for a limited number of clinical stages (P < .05). Improvement of mean RER relative enhancement ratio (r = 0.63, P = .0002) and mean wash-in time (r = -0.75, P < .0001) was significantly correlated with forced expiratory volume.
  
  
  CONCLUSIONS
  Dynamic oxygen-enhanced MR imaging has potential as a tool for assessment of clinical stage and evaluation of pulmonary functional change due to treatment in patients with asthma.
authors.affiliation: From the Advanced Biomedical Imaging Research Center (Y.O., M.N., T.Y., S.M., K.S.), Division of Functional and Diagnostic Imaging Research, Department of Radiology (Y.O., M.N., T.Y., S.M.), and Division of Radiology, Department of Radiology (H.K., S.S.), Kobe University Graduate School of Medicine, Kobe, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan; and Philips Electronics Japan, Tokyo, Japan (M.O., M.v.C.).
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.forename: Mizuho
authors.initials: M
authors.lastname: Nishio
authors.forename: Hisanobu
authors.initials: H
authors.lastname: Koyama
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Seki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Sumiaki
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Makoto
authors.initials: M
authors.lastname: Obara
authors.forename: Marc
authors.initials: M
authors.lastname: van Cauteren
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000503:physiopathology* / Q000628:therapy*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed / Q000379:methods*