Computed-tomography findings of emphysema: correlation with spirometric values

There is increasing interest in using multichannel computed-tomography scanning in the characterization of subjects with chronic obstructive pulmonary disease. Three distinct components - emphysema, large-airway inflammation and small-airway abnormality - have been evaluated using qualitative and quantitative approaches. Here we highlight computed-tomography findings of chronic obstructive pulmonary disease and correlation with spirometric values.

A considerable percentage of the subjects with emphysema detected by computed-tomography screening had normal spirometry. Severity of emphysema varies widely, even with same disease stage in chronic obstructive pulmonary disease. Studies of the relationship between high-resolution computed-tomography lung-attenuation measurements acquired under spirometric control of inspiratory and expiratory lung volume and pulmonary function showed that inspiratory measurements assess the extent of emphysema and that expiratory measurements reflect airflow limitation and air trapping. The evaluation using three-dimensional computed tomography demonstrates that airflow limitation is more closely related to the dimensions of small airways than large airways.

Volumetric computed-tomography scans allow diagnosis and quantification of the individual small airway and emphysema phenotypes present in people with chronic obstructive pulmonary disease. New computed-tomography scanning techniques should provide new insights into further understanding of the heterogeneity of chronic obstructive pulmonary disease.