title: New insight into the assessment of asthma using xenon ventilation computed tomography.
abstract: BACKGROUND
  Image analyses include computed tomography (CT), magnetic resonance imaging, and xenon ventilation CT, which is new modality to evaluate pulmonary functional imaging.
  
  
  OBJECTIVE
  To examine the usefulness of dual-energy xenon ventilation CT in asthmatic patients.
  
  
  METHODS
  A total of 43 patients 18 years or older who were nonsmokers were included in the study. Xenon CT images in wash-in and wash-out phases were obtained at baseline and after inhalation of methacholine and salbutamol. The degrees of ventilation defects and xenon trappings were evaluated through visual analysis.
  
  
  RESULTS
  Ventilation defects and xenon trapping were significantly increased and decreased after methacholine challenge and salbutamol inhalation, respectively (P < .005). The ventilation abnormalities were not significantly related to the percentage of forced expiratory volume in 1 second (FEV1) or the ratio of FEV1 to forced vital capacity. Xenon trappings after salbutamol inhalation were negatively related to the scores of the asthma control test, wheezing, or night symptoms, with statistical significance (P < .05), whereas, FEV1 showed no significant correlation with symptom scores. Baseline FEV1 was significantly lower and dyspnea and wheezing were more severe in the non-full reversal group than in the full reversal group after salbutamol inhalation in xenon CT (P < .05). The degree of ventilation defects were positively correlated with FEV1 improvement after 3 months of treatment (P = .02).
  
  
  CONCLUSIONS
  The results of this study suggest that xenon ventilation CT can be used as a new method to assess ventilation abnormalities in asthma, and these ventilation abnormalities can be used as novel parameters that reflect the status of asthma control and symptom severity.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jae-Woo
authors.initials: JW
authors.lastname: Jung
authors.forename: Jae-Woo
authors.initials: JW
authors.lastname: Kwon
authors.forename: Tae-Wan
authors.initials: TW
authors.lastname: Kim
authors.forename: So-Hee
authors.initials: SH
authors.lastname: Lee
authors.forename: Kyung-Mook
authors.initials: KM
authors.lastname: Kim
authors.forename: Hye-Ryun
authors.initials: HR
authors.lastname: Kang
authors.forename: Heung-Woo
authors.initials: HW
authors.lastname: Park
authors.forename: Chang-Hyun
authors.initials: CH
authors.lastname: Lee
authors.forename: Jin-Mo
authors.initials: JM
authors.lastname: Goo
authors.forename: Kyung-Up
authors.initials: KU
authors.lastname: Min
authors.forename: Sang-Heon
authors.initials: SH
authors.lastname: Cho
mesh_terms: D001249:Asthma / Q000000981:diagnostic imaging*; D001985:Bronchial Provocation Tests; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012123:Pulmonary Ventilation / Q000502:physiology; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014978:Xenon
chemical_list: D014978:Xenon