title: The low attenuation area on dual-energy perfusion CT: correlation with the pulmonary function tests and quantitative CT measurements.
abstract: OBJECTIVE
  To retrospectively investigate the distribution of the low attenuation area (LAA) on dual energy perfusion CT (DEpCT) in comparison with the results of pulmonary function tests (PFTs) and quantitative CT measurements.
  
  
  METHODS
  Twenty-eight patients (15 male and 13 female; mean age: 62.21 years) underwent DEpCT and PFTs within a 1-month interval. The ranges of the LAA on DEpCT were classified into six groups with attenuation values of 0-3, 0-5, 0-8, 0-10, 0-13 and 0-15 HU and the ratios of LAA in each group were compared with the percentage of forced expiratory volume in the 1st second (%FEV(1.0)), FEV(1.0)/forced vital capacity (FEV(1.0)/FVC) and the relative area of the lung with attenuation coefficients lower than -950 HU (RA(-950)).
  
  
  RESULTS
  The LAAs on the DEpCT images were significantly correlated with the RA(-950), %FEV(1.0) and FEV(1.0)/FVC, and the regression analysis showed that the best values of LAA on DEpCT were 0-10 HU with RA(-950) (r=0.63), 0-8 HU with %FEV(1.0) (r=-0.52) and 0-8HU with FEV(1.0)/FVC (r=-0.61) per patient.
  
  
  CONCLUSIONS
  The iodine disturbance on DEpCT had a moderate correlation with the results of the PFTs and RA(-950), but further examination would be needed for evaluation of iodine distribution.
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine, Japan. radokada@yamaguchi-u.ac.jp
authors.forename: Munemasa
authors.initials: M
authors.lastname: Okada
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Kunihiro
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Naofumi
authors.initials: N
authors.lastname: Matsunaga
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Sano
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Yuasa
authors.forename: Akiko
authors.initials: A
authors.lastname: Narazaki
authors.forename: Shohei
authors.initials: S
authors.lastname: Kudomi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Koike
authors.forename: Shoji
authors.initials: S
authors.lastname: Kido
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging / Q000379:methods*; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult