title: Xenon-enhanced CT using subtraction CT: Basic and preliminary clinical studies for comparison of its efficacy with that of dual-energy CT and ventilation SPECT/CT to assess regional ventilation and pulmonary functional loss in smokers.
abstract: OBJECTIVE
  To prospectively and directly compare the capability for assessments of regional ventilation and pulmonary functional loss in smokers of xenon-ventilation CT obtained with the dual-energy CT (DE-CT) and subtraction CT (Sub-CT) MATERIALS AND METHODS: Twenty-three consecutive smokers (15 men and 8 women, mean age: 69.7±8.7years) underwent prospective unenhanced and xenon-enhanced CTs, the latter by Sub-CT and DE-CT methods, ventilation SPECT and pulmonary function tests. Sub-CT was generated from unenhanced and xenon-enhanced CT, and all co-registered SPECT/CT data were produced from SPECT and unenhanced CT data. For each method, regional ventilation was assessed by using a 11-point scoring system on a per-lobe basis. To determine the functional lung volume by each method, it was also calculated for individual sublets with a previously reported method. To determine inter-observer agreement for each method, ventilation defect assessment was evaluated by using the χ2 test with weighted kappa statistics. For evaluation of the efficacy of each method for pulmonary functional loss assessment, functional lung volume was correlated with%FEV1.
  
  
  RESULTS
  Each inter-observer agreement was rated as substantial (Sub-CT: κ=0.69, p<0.0001; DE-CT: κ=0.64, p<0.0001; SPECT/CT: κ=0.64, p<0.0001). Functional lung volume for each method showed significant to good correlation with%FEV1(Sub-CT: r=0.72, p=0.0001; DE-CT: r=0.74, p<0.0001; SPECT/CT: r=0.66, p=0.0006).
  
  
  CONCLUSIONS
  Xenon-enhanced CT obtained by Sub-CT can be considered at least as efficacious as that obtained by DE-CT and SPECT/CT for assessment of ventilation abnormality and pulmonary functional loss in smokers.
authors.affiliation: Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan; Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan. Electronic address: yosirad@kobe-u.ac.jp.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.affiliation: Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan; Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.affiliation: Department of Radiology, Hyogo Cancer Center, Akashi, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takenaka
authors.affiliation: Toshiba Medical Systems Corporation, Otawara, Japan.
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Fujisawa
authors.affiliation: Toshiba Medical Systems Corporation, Otawara, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Sugihara
authors.affiliation: Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kishida
authors.affiliation: Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Seki
authors.affiliation: Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Japan.
authors.forename: Hisanobu
authors.initials: H
authors.lastname: Koyama
authors.affiliation: Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Japan.
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D015588:Observer Variation; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012123:Pulmonary Ventilation; D012119:Respiration; D012129:Respiratory Function Tests; D000072098:Single Photon Emission Computed Tomography Computed Tomography / Q000379:methods*; D012907:Smoking / Q000009:adverse effects* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014978:Xenon
chemical_list: D003287:Contrast Media; D014978:Xenon
keywords: COPD; CT; Lung; SPECT; Ventilation