title: Parametric response mapping on chest computed tomography associates with clinical and functional parameters in chronic obstructive pulmonary disease.
abstract: In the search for specific phenotypes of chronic obstructive pulmonary disease (COPD) computed tomography (CT) derived Parametric Response Mapping (PRM) has been introduced. This study evaluates the association between PRM and currently available biomarkers of disease severity in COPD.
  
  
  
  Smokers with and without COPD were characterized based on questionnaires, pulmonary function tests, body plethysmography, and low-dose chest CT scanning. PRM was used to calculate the amount of emphysema (PRMEmph) and non-emphysematous air trapping (i.e. functional small airway disease, PRMfSAD). PRM was first compared with other biomarkers for emphysema (Perc15) and air trapping (E/I-ratioMLD). Consequently, linear regression models were utilized to study associations of PRM measurements with clinical parameters.
  
  
  
  166 participants were included with a mean ± SD age of 50.5 ± 17.7 years. Both PRMEmphand PRMfSADwere more strongly correlated with lung function parameters as compared to Perc15 and E/I-ratioMLD. PRMEmphand PRMfSADwere higher in COPD participants than non-COPD participants (14.0% vs. 1.1%, and 31.6% vs. 8.2%, respectively, both p < 0.001) and increased with increasing GOLD stage (all p < 0.001). Multivariate analysis showed that PRMfSADwas mainly associated with total lung capacity (TLC) (β = -7.90, p < 0.001), alveolar volume (VA) (β = 7.79, p < 0.001), and residual volume (β = 6.78, p < 0.001), whilst PRMEmphwas primarily associated with Kco (β = 8.95, p < 0.001), VA (β = -6.21, p < 0.001), and TLC (β = 6.20, p < 0.001).
  
  
  
  PRM strongly associates with the presence and severity of COPD. PRM therefore appears to be a valuable tool in differentiating COPD phenotypes.
authors.affiliation: Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: e.pompe@umcutrecht.nl.
authors.forename: Esther
authors.initials: E
authors.lastname: Pompe
authors.affiliation: Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Center for Molecular Imaging, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Galbán
authors.affiliation: Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Center for Molecular Imaging, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Ross
authors.affiliation: Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Leo
authors.initials: L
authors.lastname: Koenderman
authors.affiliation: University of Groningen, University Medical Center Groningen, Department of Pulmonary Disease, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, The Netherlands.
authors.forename: Nick Ht
authors.initials: NH
authors.lastname: Ten Hacken
authors.affiliation: University of Groningen, University Medical Center Groningen, Department of Pulmonary Disease, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, The Netherlands.
authors.forename: Dirkje S
authors.initials: DS
authors.lastname: Postma
authors.affiliation: University of Groningen, University Medical Center Groningen, Department of Pulmonary Disease, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, The Netherlands.
authors.forename: Maarten
authors.initials: M
authors.lastname: van den Berge
authors.affiliation: Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Pim A
authors.initials: PA
authors.lastname: de Jong
authors.affiliation: Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Jan-Willem J
authors.initials: JJ
authors.lastname: Lammers
authors.affiliation: Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Firdaus Aa
authors.initials: FA
authors.lastname: Mohamed Hoesein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging / Q000503:physiopathology; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014797:Vital Capacity / Q000502:physiology; D055815:Young Adult
keywords: Computed tomography; Copd; Emphysema; Parametric response mapping; Phenotypes; Small airway disease