The computed tomographic (CT) densities of imaged structures are a function of the CT scanning protocol, the structure size, and the structure density. For objects of the same magnitude as the scanner point spread function (PSF), CT will underestimate true structure density. Prior investigation suggests that this process, termed contrast reduction, could be used to estimate the strength of thin structures such as cortical bone. In this investigation, we endeavored to exploit this process to provide a CT based measure of airway disease that can assess changes in airway wall thickening and density that may be associated with the mural remodeling process in subjects with chronic obstructive pulmonary disease (COPD). An initial computer based study using a range of simulated airway wall sizes and densities suggested that CT measures of airway wall attenuation could detect changes in both wall thickness and structure density. A second phantom based study was performed using a series of Polycarbonate tubes of known density. The results of this again demonstrated the process of contrast reduction and further validated the computer based simulation. Finally, measures of airway wall attenuation, wall thickness, and wall area divided by total cross sectional area - wall area percent (WA%), were performed in a cohort of 224 subjects with COPD and correlated with spirometric measures of lung function. The results suggest that wall attenuation is comparable to WA% in predicting lung function and that it may offer complimentary information to WA% in characterizing airway disease in subjects with COPD.