Quantitative assessment of regional emphysema distribution in patients with chronic obstructive pulmonary disease (COPD).

ABSTRACT

PURPOSE: To compare objective and subjective assessment of the distribution of emphysema in unselected patients with chronic obstructive pulmonary disease (COPD). MATERIAL AND METHODS: 167 patients were computed tomography (CT) scanned, and the relative area (RA-910) of emphysema in each CT slice was plotted against table position. The craniocaudal distribution was calculated as the slope of the regression line, and grouped as upper-lung-zone predominance (ULP), lower-lung-zone predominance (LLP), or mild/homogeneous distribution (MHE). CT scans were also classified as ULP, LLP, and MHE based on visual assessment of three high-resolution CT (HRCT) slices, and the leading pattern of emphysema was classified as centrilobular (CLE), paraseptal (PSE), panlobular (PLE), or no emphysema (NE). RESULTS: By objective classification, scans were divided into almost equal numbers of ULP, LLP, and MHE, whereas visual evaluation classified more scans as ULP (P<0.001) and very few as LLP (P<0.0001). In patients with CLE, 49% had ULP by objective classification, whereas LLP was the commonest leading pattern in PSE, PLE, and NE. CONCLUSION: We found significant discrepancies between the objective and subjective distributions of emphysema in various morphological patterns, which may be of clinical importance in, for instance, lung-volume-reduction surgery.