CT metrics of airway disease and emphysema in severe COPD.
BACKGROUND
CT scan measures of emphysema and airway disease have been correlated with lung function in cohorts of subjects with a range of COPD severity. The contribution of CT scan-assessed airway disease to objective measures of lung function and respiratory symptoms such as dyspnea in severe emphysema is less clear.


METHODS
Using data from 338 subjects in the National Emphysema Treatment Trial (NETT) Genetics Ancillary Study, densitometric measures of emphysema using a threshold of -950 Hounsfield units (%LAA-950) and airway wall phenotypes of the wall thickness (WT) and the square root of wall area (SRWA) of a 10-mm luminal perimeter airway were calculated for each subject. Linear regression analysis was performed for outcome variables FEV(1) and percent predicted value of FEV(1) with CT scan measures of emphysema and airway disease.


RESULTS
In univariate analysis, there were significant negative correlations between %LAA-950 and both the WT (r = -0.28, p = 0.0001) and SRWA (r = -0.19, p = 0.0008). Airway wall thickness was weakly but significantly correlated with postbronchodilator FEV(1)% predicted (R = -0.12, p = 0.02). Multivariate analysis showed significant associations between either WT or SRWA (beta = -5.2, p = 0.009; beta = -2.6, p = 0.008, respectively) and %LAA-950 (beta = -10.6, p = 0.03) with the postbronchodilator FEV(1)% predicted. Male subjects exhibited significantly thicker airway wall phenotypes (p = 0.007 for WT and p = 0.0006 for SRWA).


CONCLUSIONS
Airway disease and emphysema detected by CT scanning are inversely related in patients with severe COPD. Airway wall phenotypes were influenced by gender and associated with lung function in subjects with severe emphysema.
Kim
Woo Jin
WJ
Department of Internal Medicine, Kangwon National University, Chuncheon, South Korea.
Silverman
Edwin K
EK
Channing Laboratory, Brigham and Women's Hospital, Boston, MA; Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, MA.
Hoffman
Eric
E
Department of Radiology, University of Iowa, Iowa City, IA.
Criner
Gerard J
GJ
Division of Pulmonary and Critical Care Medicine, Temple University Hospital, Philadelphia, PA.
Mosenifar
Zab
Z
Division of Pulmonary Medicine, Cedars-Sinai Medical Center, Los Angeles, CA.
Sciurba
Frank C
FC
Division of Pulmonary and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA.
Make
Barry J
BJ
Division of Pulmonary Sciences and Critical Care Medicine, National Jewish Medical & Research Center, Denver, CO.
Carey
Vincent
V
Channing Laboratory, Brigham and Women's Hospital, Boston, MA.
San José Estépar
Raúl
R
Department of Radiology, Brigham and Women's Hospital, Boston, MA.
Diaz
Alejandro
A
Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, MA.
Reilly
John J
JJ
Division of Pulmonary and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA.
Martinez
Fernando J
FJ
Division of Pulmonary and Critical Care Medicine, University of Michigan Medical Center, Ann Arbor, MI.
Washko
George R
GR
Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, MA. Electronic address: GWashko@Partners.org.
D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000000981:diagnostic imaging / Q000503:physiopathology; D000704:Analysis of Variance; D015331:Cohort Studies; D004417:Dyspnea / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011336:Probability; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012123:Pulmonary Ventilation / Q000502:physiology*; D012129:Respiratory Function Tests; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D014109:Total Lung Capacity / Q000502:physiology