Objective    To study the effect of imaging parameters of 16-slice CT on lung volumetry and density measurement.     Methods    Fifty cases were included and divided into 2 groups. In 30 cases of Group A

total lung volume (V) and mean lung density (MLD) were measured with different slice thickness

reconstruction algorithms and imaging threshold. In 20 cases and 40 unilateral lungs of Group B

partial lung volume (Vp) and MLD were measured with different scan doses

reconstruction algorithms and imaging threshold.     Results    There were highly significant differences of V and MLD between 1.25 mm and 10 mm slice thickness

the V and MLD measured with 1.25 mm slice thickness were smaller than with 10mm thickness (P=0.000). The effect of scan dose was significant on lung volume analysis but insignificant on MLD

the Vp measured with low dose scan was smaller than with conventional dose (P=0.001). Reconstruction algorithms affected lung volume and density analysis significantly

the Vp and MLD obtained with bone algorithms was smaller than with standard algorithms (P0.05 ).     Conclusion    Quantitative analysis of lung volume and density using 16-slice CT is correlated significantly with imaging parameters. Slice thickness of 1.25 mm

low dose scan of 60 mAs and standard algorithms reconstruction can meet the requirements of quantitative analysis and reduce the radiation to patients.