We thank Dr Hochhegger and colleagues for their comments on our recent article in CHEST.1 The research conducted aimed to highlight that COPD is a heterogeneous condition and requires a multidimensional approach to characterization. CT scanning is now emerging as an important noninvasive tool in the multidimensional approach to phenotyping COPD, and our study demonstrated that spirometry and physiologic assessments alone could not differentiate between the radiologic phenotypes that exist within COPD. In particular, the study found that there was a great overlap in the detection of bronchiectasis, bronchial wall thickening, and emphysema in subjects with COPD. In their correspondence, Dr Hochhegger and colleagues correctly point out that there is a superior role of emphysema description using quantitative CT scan analysis; however, there is a recognized difficulty in quantification of airway wall dimensions required for bronchial wall thickening and bronchiectasis in COPD.2 In our study, we have defined the presence of bronchiectasis, bronchial wall thickening, and emphysema using established international thoracic radiologic guidelines,3 and more importantly, we have previously demonstrated that at our institution, the interobserver correlation of diagnosis of emphysema, bronchial wall thickening, and bronchiectasis is good4 while using tools widely available in clinical practice. This is particularly important because COPD is defined by chronic airflow limitation, which can include parenchymal destruction or airway wall thickening.