title: Patterns of Emphysema Heterogeneity.
abstract: BACKGROUND
  Although lobar patterns of emphysema heterogeneity are indicative of optimal target sites for lung volume reduction (LVR) strategies, the presence of segmental, or sublobar, heterogeneity is often underappreciated.
  
  
  OBJECTIVE
  The aim of this study was to understand lobar and segmental patterns of emphysema heterogeneity, which may more precisely indicate optimal target sites for LVR procedures.
  
  
  METHODS
  Patterns of emphysema heterogeneity were evaluated in a representative cohort of 150 severe (GOLD stage III/IV) chronic obstructive pulmonary disease (COPD) patients from the COPDGene study. High-resolution computerized tomography analysis software was used to measure tissue destruction throughout the lungs to compute heterogeneity (≥15% difference in tissue destruction) between (inter-) and within (intra-) lobes for each patient. Emphysema tissue destruction was characterized segmentally to define patterns of heterogeneity.
  
  
  RESULTS
  Segmental tissue destruction revealed interlobar heterogeneity in the left lung (57%) and right lung (52%). Intralobar heterogeneity was observed in at least one lobe of all patients. No patient presented true homogeneity at a segmental level. There was true homogeneity across both lungs in 3% of the cohort when defining heterogeneity as ≥30% difference in tissue destruction.
  
  
  CONCLUSIONS
  Many LVR technologies for treatment of emphysema have focused on interlobar heterogeneity and target an entire lobe per procedure. Our observations suggest that a high proportion of patients with emphysema are affected by interlobar as well as intralobar heterogeneity. These findings prompt the need for a segmental approach to LVR in the majority of patients to treat only the most diseased segments and preserve healthier ones.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Ludwig Boltzmann Institute for COPD, Otto Wagner Hospital, Vienna, Austria.
authors.forename: Arschang
authors.initials: A
authors.lastname: Valipour
authors.forename: Pallav L
authors.initials: PL
authors.lastname: Shah
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Gesierich
authors.forename: Ralf
authors.initials: R
authors.lastname: Eberhardt
authors.forename: Greg
authors.initials: G
authors.lastname: Snell
authors.forename: Charlie
authors.initials: C
authors.lastname: Strange
authors.forename: Robert
authors.initials: R
authors.lastname: Barry
authors.forename: Avina
authors.initials: A
authors.lastname: Gupta
authors.forename: Erik
authors.initials: E
authors.lastname: Henne
authors.forename: Sourish
authors.initials: S
authors.lastname: Bandyopadhyay
authors.forename: Philippe
authors.initials: P
authors.lastname: Raffy
authors.forename: Youbing
authors.initials: Y
authors.lastname: Yin
authors.forename: Juerg
authors.initials: J
authors.lastname: Tschirren
authors.forename: Felix J F
authors.initials: FJ
authors.lastname: Herth
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods