Computer-aided measurements of pulmonary emphysema in chest multidetector-row spiral computed tomography: effect of image reconstruction parameters.

Objective: To evaluate the effect of different image reconstruction parameters on quantitative automated measurements of pulmonary emphysema in chest multidetector-row spiral computed tomography.

Materials And Methods: Thirty patients with known emphysema underwent multidetector-row spiral computed tomography. Retrospective reconstruction with a soft tissue kernel (Siemens B20 at 1-mm, 2-mm, and 3-mm slices) and 4 alternative kernel grades (from smooth to sharp: Siemens B30, B40, B50, B60 at 1-mm slices) was performed. Total lung volume, emphysema volume (EV), 15th percentile density, and 4 EV clusters were quantified. Results were compared with those of standard algorithm B20/1-mm slices.

Results: Differences in total lung volume were less than 0.2%. Alternative kernel grades resulted in a significantly increased average EV. The 15th percentile density showed a significant average difference for all alternative algorithms. The large emphysema cluster showed a significant change for reconstruction algorithms B50, B60, B20/2 mm and B20/3 mm.

Conclusions: Pulmonary EV is significantly affected by different reconstruction algorithms.