title: The role of CT scanning in multidimensional phenotyping of COPD.
abstract: BACKGROUND
  COPD is a heterogeneous disease characterized by airflow obstruction and diagnosed by lung function. CT imaging is emerging as an important, noninvasive tool in phenotyping COPD. However, the use of CT imaging in defining the disease heterogeneity above lung function is not fully known.
  
  
  METHODS
  Seventy-five patients with COPD (58 men, 17 women) were studied with CT imaging and with measures of airway inflammation. Airway physiology and health status were also determined.
  
  
  RESULTS
  The presence of emphysema (EM), bronchiectasis (BE), and bronchial wall thickening (BWT) was found in 67%, 27%, and 27% of subjects, respectively. The presence of EM was associated with lower lung function (mean difference % FEV(1), -20%; 95% CI, -28 to -11; P < .001). There was no difference in airway inflammation, exacerbation frequency, or bacterial load in patients with EM alone or with BE and/or BWT ± EM. The diffusing capacity of the lung for carbon monoxide/alveolar volume ratio was the most sensitive and specific parameter in identifying EM (area under the receiver operator characteristic curve, 0.87; 95% CI, 0.79-0.96). Physiologic cluster analysis identified three clusters, two of which were EM predominant and the third characterized by a heterogeneous combination of EM and BE.
  
  
  CONCLUSIONS
  The application of CT imaging can be useful as a tool in the multidimensional approach to phenotyping patients with COPD.
authors: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, England.
authors: Mona
authors: M
authors: Bafadhel
authors: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, England.
authors: Imran
authors: I
authors: Umar
authors: Department of Radiology, University Hospitals of Leicester NHS Trust, Leicester, England.
authors: Sumit
authors: S
authors: Gupta
authors: Department of Radiology, University Hospitals of Leicester NHS Trust, Leicester, England.
authors: J Vimal
authors: JV
authors: Raj
authors: Department of Respiratory Physiology, University Hospitals of Leicester NHS Trust, Leicester, England.
authors: Dhiraj D
authors: DD
authors: Vara
authors: Department of Radiology, University Hospitals of Leicester NHS Trust, Leicester, England.
authors: James J
authors: JJ
authors: Entwisle
authors: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, England.
authors: Ian D
authors: ID
authors: Pavord
authors: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, England.
authors: Christopher E
authors: CE
authors: Brightling
authors: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, England. Electronic address: salman95@yahoo.com.
authors: Salman
authors: S
authors: Siddiqui
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001987:Bronchiectasis / Q000000981:diagnostic imaging; D001995:Bronchography; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D025341:Principal Component Analysis; D011653:Pulmonary Diffusing Capacity; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging*; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging; D011788:Quality of Life; D012372:ROC Curve; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed