title: Chronic obstructive pulmonary disease: quantitative and visual ventilation pattern analysis at xenon ventilation CT performed by using a dual-energy technique.
abstract: OBJECTIVE
  To evaluate the potential of xenon ventilation computed tomography (CT) in the quantitative and visual analysis of chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  This study was approved by the institutional review board. After informed consent was obtained, 32 patients with COPD underwent CT performed before the administration of xenon, two-phase xenon ventilation CT with wash-in (WI) and wash-out (WO) periods, and pulmonary function testing (PFT). For quantitative analysis, results of PFT were compared with attenuation parameters from prexenon images and xenon parameters from xenon-enhanced images in the following three areas at each phase: whole lung, lung with normal attenuation, and low-attenuating lung (LAL). For visual analysis, ventilation patterns were categorized according to the pattern of xenon attenuation in the area of structural abnormalities compared with that in the normal-looking background on a per-lobe basis: pattern A consisted of isoattenuation or high attenuation in the WI period and isoattenuation in the WO period; pattern B, isoattenuation or high attenuation in the WI period and high attenuation in the WO period; pattern C, low attenuation in both the WI and WO periods; and pattern D, low attenuation in the WI period and isoattenuation or high attenuation in the WO period.
  
  
  RESULTS
  Among various attenuation and xenon parameters, xenon parameters of the LAL in the WO period showed the best inverse correlation with results of PFT (P < .0001). At visual analysis, while emphysema (which affected 99 lobes) commonly showed pattern A or B, airway diseases such as obstructive bronchiolitis (n = 5) and bronchiectasis (n = 2) and areas with a mucus plug (n = 1) or centrilobular nodules (n = 5) showed pattern D or C.
  
  
  CONCLUSIONS
  WI and WO xenon ventilation CT is feasible for the simultaneous regional evaluation of structural and ventilation abnormalities both quantitatively and qualitatively in patients with COPD.
authors.affiliation: Department of Radiology, Interdisciplinary Program in Radiation Applied Life Science, Healthcare Gangnam Center, Seoul National University Hospital, Seoul National University College of Medicine, Seoul 110-744, Korea.
authors.forename: Eun-Ah
authors.initials: EA
authors.lastname: Park
authors.forename: Jin Mo
authors.initials: JM
authors.lastname: Goo
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Park
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Lee
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Lee
authors.forename: Chang Min
authors.initials: CM
authors.lastname: Park
authors.forename: Chul-Gyu
authors.initials: CG
authors.lastname: Yoo
authors.forename: Jong Hyo
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging*; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014978:Xenon
chemical_list: D014978:Xenon