title: Pulmonary emphysema subtypes on computed tomography: the MESA COPD study.
abstract: BACKGROUND
  Pulmonary emphysema is divided into 3 major subtypes at autopsy: centrilobular, paraseptal, and panlobular emphysema. These subtypes can be defined by visual assessment on computed tomography (CT); however, clinical characteristics of emphysema subtypes on CT are not well defined. We developed a reliable approach to visual assessment of emphysema subtypes on CT and examined if emphysema subtypes have distinct characteristics.
  
  
  METHODS
  The Multi-Ethnic Study of Atherosclerosis COPD Study recruited smokers with chronic obstructive pulmonary disease (COPD) and controls ages 50-79 years with ≥ 10 pack-years. Participants underwent CT following a standardized protocol. Definitions of centrilobular, paraseptal, and panlobular emphysema were obtained by literature review. Six-minute walk distance and pulmonary function were performed following guidelines.
  
  
  RESULTS
  Twenty-seven percent of 318 smokers had emphysema on CT. Interrater reliability of emphysema subtype was substantial (K: 0.70). Compared with participants without emphysema, individuals with centrilobular or panlobular emphysema had greater dyspnea, reduced walk distance, greater hyperinflation, and lower diffusing capacity. In contrast, individuals with paraseptal emphysema were similar to controls, except for male predominance. Centrilobular, but not panlobular or paraseptal, emphysema was associated with greater smoking history (+21 pack-years P <.001). Panlobular, but not other types of emphysema, was associated with reduced body mass index (-5 kg/m(2); P = .01). Other than for dyspnea, these findings were independent of the forced expiratory volume in 1 second. Seventeen percent of smokers without COPD on spirometry had emphysema, which was independently associated with reduced walk distance.
  
  
  CONCLUSIONS
  Emphysema subtypes on CT are common in smokers with and without COPD. Centrilobular and panlobular emphysema, but not paraseptal emphysema, have considerable symptomatic and physiological consequences.
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY; Department of Medicine, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Smith
authors.affiliation: Department of Radiology, College of Physicians and Surgeons, Columbia University, New York, NY.
authors.forename: John H M
authors.initials: JH
authors.lastname: Austin
authors.affiliation: Department of Radiology, University of Iowa Carver College of Medicine, Iowa City.
authors.forename: John D
authors.initials: JD
authors.lastname: Newell
authors.affiliation: Department of Radiology, College of Physicians and Surgeons, Columbia University, New York, NY.
authors.forename: Belinda M
authors.initials: BM
authors.lastname: D'Souza
authors.affiliation: Department of Radiology, College of Physicians and Surgeons, Columbia University, New York, NY.
authors.forename: Anna
authors.initials: A
authors.lastname: Rozenshtein
authors.affiliation: Department of Radiology, University of Iowa Carver College of Medicine, Iowa City.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Hoffman
authors.affiliation: Department of Radiology, College of Physicians and Surgeons, Columbia University, New York, NY.
authors.forename: Firas
authors.initials: F
authors.lastname: Ahmed
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY. Electronic address: rgb9@mail.cumc.columbia.edu.
authors.forename: R Graham
authors.initials: RG
authors.lastname: Barr
mesh_terms: D000368:Aged; D004417:Dyspnea / Q000209:etiology; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000150:complications / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D013147:Spirometry; D014057:Tomography, X-Ray Computed; D016138:Walking
keywords: Centrilobular; Computed tomography; Emphysema; Panlobular; Paraseptal