title: Xenon-Enhanced Dual-Energy CT Imaging in Combined Pulmonary Fibrosis and Emphysema.
abstract: BACKGROUND
  Little has been reported on the feasibility of xenon-enhanced dual-energy computed tomography (Xe-DECT) in the visual and quantitative analysis of combined pulmonary fibrosis and emphysema (CPFE).
  
  
  OBJECTIVE
  We compared CPFE with idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), as well as correlation with parameters of pulmonary function tests (PFTs).
  
  
  METHODS
  Studied in 3 groups were 25 patients with CPFE, 25 with IPF without emphysema (IPF alone), 30 with COPD. Xe-DECT of the patients' entire thorax was taken from apex to base after a patient's single deep inspiration of 35% stable nonradioactive xenon. The differences in several parameters of PFTs and percentage of areas enhanced by xenon between 3 groups were compared and analyzed retrospectively.
  
  
  RESULTS
  The percentage of areas enhanced by xenon in both lungs were calculated as CPFE/IPF alone/COPD = 72.2 ± 15.1% / 82.2 ± 14.7% /45.2 ± 23.2%, respectively. In the entire patients, the percentage of areas enhanced by xenon showed significantly a positive correlation with FEV1/FVC (R = 0.558, P < 0.0001) and %FEV1, (R = 0.528, P < 0.0001) and a negative correlation with %RV (R = -0.594, P < 0.0001) and RV/TLC (R = -0.579, P < 0.0001). The percentage of areas enhanced by xenon in patients with CPFE showed significantly a negative correlation with RV/TLC (R = -0.529, P = 0.007). Xenon enhancement of CPFE indicated 3 different patterns such as upper predominant, diffuse, and multifocal defect. The percentage of areas enhanced by xenon in upper predominant defect pattern was significantly higher than that in diffuse defect and multifocal defect pattern among these 3 different patterns in CPFE.
  
  
  CONCLUSIONS
  The percentage of areas enhanced by xenon demonstrated strong correlations with obstructive ventilation impairment. Therefore, we conclude that Xe-DECT may be useful for distinguishing emphysema lesion from fibrotic lesion in CPFE.
authors.affiliation: Department of Respiratory Medicine, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: Keishi
authors.identifier: http://orcid.org/0000-0003-3688-6782
authors.initials: K
authors.lastname: Sugino
authors.affiliation: Department of Diagnostic Radiology, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Department of Respiratory Medicine, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Respiratory Medicine, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Gocho
authors.affiliation: Department of Respiratory Medicine, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Ishida
authors.affiliation: Department of Respiratory Medicine, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Isobe
authors.affiliation: Department of Diagnostic Radiology, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Shiraga
authors.affiliation: Department of Respiratory Medicine, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: Sakae
authors.initials: S
authors.lastname: Homma
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004646:Emphysema / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014978:Xenon
chemical_list: D014978:Xenon