title: Quantitative and qualitative assessments of lung destruction and pulmonary functional loss from reduced-dose thin-section CT in pulmonary emphysema patients.
abstract: OBJECTIVE
  Academic and clinical interest in reducing radiation from computed tomography (CT) examinations has increased, and the purpose of this study was to determine the capabilities of reduced-dose multidetector-row CT (MDCT) in assessing lung destruction and pulmonary functional loss in pulmonary emphysema patients.
  
  
  METHODS
  Twenty-five consecutive smokers (15 men and 10 women; mean age 67.9 years; age range 49-86 years) underwent MDCT examinations using two different effective tube currents (standard-dose protocol [150 mAs] and reduced-dose protocol [50 mAs]). For quantitative and qualitative assessments of lung destruction in each subject, percentage of low attenuation emphysematous destruction areas (%LAAs) were computationally calculated, and visual emphysema scores (ESs) were determined for both protocols. To determine the capabilities for quantitative and qualitative assessments of lung destruction by using reduced-dose protocol, %LAAs and ESs of both protocols were compared statistically. To compare the capabilities for quantitative and qualitative assessments of pulmonary functional loss, %LAAs and ESs of both protocols were correlated with forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC).
  
  
  RESULTS
  %LAAs and ESs had significant correlations between both protocols (%LAAs: r = 0.95, P < .001; ESs: r = 0.97, P < .001). The limits of agreement of %LAAs were -1.8 + or - 9.2%. The agreement of ESs between both protocols was substantial (kappa = 0.70). %LAAs and ESs of both protocols had significant correlations with FEV1/FVC (%LAAs of 150 mAs: r = -0.49, P < .05; %LAAs of 50 mAs: r = -0.44, P < .05; ESs of 150 mAs: r = -0.67, P < .001; ESs of 50 mAs: r = -0.66, P < .001).
  
  
  CONCLUSIONS
  Reduced-dose MDCT had a potential of substitution for standard-dose MDCT on the both assessments in pulmonary emphysema patients.
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan. hkoyama@med.kobe-u.ac.jp
authors.forename: Hisanobu
authors.initials: H
authors.lastname: Koyama
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.forename: Youichi
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Munenobu
authors.initials: M
authors.lastname: Nogami
authors.forename: Kenya
authors.initials: K
authors.lastname: Murase
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Onishi
authors.forename: Keiko
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takenaka
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001822:Body Burden; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D055370:Lung Injury / Q000150:complications* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011656:Pulmonary Emphysema / Q000150:complications* / Q000000981:diagnostic imaging*; D011835:Radiation Protection / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*