title: Regional lung density and blood volume in nonsmoking and smoking subjects measured by PET.
abstract: Regional lung density (DL) and regional fractional pulmonary blood volume (VB) were measured quantitatively during tidal breathing in 30 healthy supine subjects (15 smokers and 15 nonsmokers) in a 1.7-cm-thick midthoracic cross section using positron emission tomography (PET) and 11CO (inhaled)-labeled erythrocytes. Regional alveolar volume (VA), extravascular lung density (DEV), and relative alveolar size (Valv = VA/DEV) were calculated. For the nonsmokers, mean values (+/- SD between subjects) for the right lung were as follows: DL, 0.28 +/- 0.03 g/cm3; DEV, 0.10 +/- 0.02 g/cm3; and Valv, 7.1 +/- 1.9 ml/g lung tissue. In the smoking subjects DEV (right plus left lung) was 16% higher. No significant difference in VB between smokers and nonsmokers was found. The differences in DEV and VB between right and left lung were not significant. Mean values (+/- SD) of the dorsal-to-ventral ratios calculated for the right lung in the nonsmokers were as follows: DL, 1.34 +/- 0.16; VA, 0.90 +/- 0.05; VB, 1.52 +/- 0.26; DEV, 1.10 +/- 0.17; and Valv, 0.85 +/- 0.19. Almost identical ratios were found in the smokers. The influence of overall thoracic expansion was investigated in one subject restudied during voluntary hyperinflation and during positive end-expiratory pressure.
mesh_terms: D000328:Adult; D000375:Aging / Q000473:pathology; D001810:Blood Volume; D001827:Body Height; D005260:Female; D006112:Gravitation; D006801:Humans; D008168:Lung / Q000033:anatomy & histology* / Q000098:blood supply / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012907:Smoking / Q000473:pathology*; D014055:Tomography, Emission-Computed