title: Quantitative assessment of pulmonary perfusion using dynamic contrast-enhanced CT in patients with chronic obstructive pulmonary disease: correlations with pulmonary function test and CT volumetric parameters.
abstract: BACKGROUND
  Pulmonary function test (PFT) is commonly used to help diagnose chronic obstructive pulmonary disease (COPD) and other lung diseases. However, it cannot be used to evaluate regional function and morphological abnormalities.
  
  
  OBJECTIVE
  To quantitatively evaluate pulmonary perfusion imaging using dynamic contrast-enhanced (DCE) computed tomography (CT) and observe its correlations with PFT and CT volumetric parameters in COPD patients.
  
  
  METHODS
  PFT and CT pulmonary perfusion examination were performed in 63 COPD patients. Perfusion defects were quantitated by calculating the CT value ratio (RHU) between perfusion defects (HUdefect) and normal lung (HUnormal). Volumetric CT data were used to calculate emphysema index (EI), total lung volume (TLV), and total emphysema volume (TEV). Emphysematous parenchyma was defined as the threshold of lung area lower than -950 HU. Correlations between RHU and TLV, TEV, EI, and PFT were assessed using Spearman correlation analysis.
  
  
  RESULTS
  The positive rate of perfusion defects on CT perfusion images was higher than that of emphysema on CT mask images (χ(2) = 17.027, P < 0.001). The Spearman correlation test showed that RHU was positively correlated with FEV1 (R = 0.59, P < 0.001), FEV1% Predicted (R = 0.61, P < 0.001), FVC (R = 0.47, P = 0.002), and FEV1/FVC (R = 0.65, P < 0.001), and negatively correlated with EI (R = -0.67, P < 0.001).
  
  
  CONCLUSIONS
  CT perfusion imaging is more sensitive in detecting emphysema that is inconspicuous on CT images. RHU is correlated with PFT and CT volumetric parameters, suggesting that it is more sensitive in detecting early COPD changes and may prove to be a potential predictor of focal lung function.
authors.affiliation: Department of Radiology, Changzheng Hospital of the Second Military Medical University, Shanghai, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Department of Radiology, Changzheng Hospital of the Second Military Medical University, Shanghai, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Department of Radiology, Changzheng Hospital of the Second Military Medical University, Shanghai, PR China fanli0930@163.com.
authors.forename: Li
authors.initials: L
authors.lastname: Fan
authors.affiliation: Department of Radiology, Changzheng Hospital of the Second Military Medical University, Shanghai, PR China.
authors.forename: Shi-yuan
authors.initials: SY
authors.lastname: Liu
authors.affiliation: Department of Radiology, Changzheng Hospital of the Second Military Medical University, Shanghai, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Radiology, Changzheng Hospital of the Second Military Medical University, Shanghai, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Respiration Medicine, Changzheng Hospital of the Second Military Medical University, Shanghai, PR China.
authors.forename: Li-ming
authors.initials: LM
authors.lastname: Zhao
authors.affiliation: Department of Respiration Medicine, Changzheng Hospital of the Second Military Medical University, Shanghai, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Li
mesh_terms: D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008168:Lung / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000379:methods / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Chronic obstructive pulmonary disease; computed tomography; emphysema; pulmonary function test