We aimed to determine the degree and extent of parenchymal abnormalities on pulmo-CT in patients with emphysema. The study group consisted of 29 patients (18 male, I I female; mean age 57.9. L 13). The diagnosis was based on clinical symptoms, pulmonary function tests (PFT) values, and chest CT findings. All of the patients CT scans were obtained during suspended deep inspiration from the apices to the costophrenic angles. The mean lung attenuation (MLD) and parenchymal abnormalities related to emphysema were quantitatively calculated with tables, histograms and graphics at the whole lung. The lung density measurements revealed a mean density of -898.48 +/- 51.37 HU in patients with emphysema and -825.1 +/- 25.5 HU in control group. In addition, mean percentage of subthreshold attenuation values was found as 12.03 +/- 15.75 and 1.07 +/- 0.83 in patients with emphysema and control group, respectively. Compared with control group, the patients with emphysema had a significantly lower inspiratory MLD (p < 0.05). Additionally, statistically significant correlations were seen between the MLD and percentage of subthreshold values (r = 0.44, p < 0.05). In contrast, there was poor correlation between PFT measurements and the subthreshold values.