Comparison of the sensitivities of 5 different computed tomography scanners for the assessment of the progression of pulmonary emphysema: a phantom study

RATIONALE AND OBJECTIVES: To compare the sensitivities of 5 different computed tomography scanners (4 multislice CT [MSCT] and 1 single-slice CT) in the assessment of the progression of pulmonary emphysema. METHODS: A Perspex cylinder phantom was constructed containing small pieces of polythene foam with densities representative of lung. Changing the cylinder's volume simulated subtle lung density changes. The sensitivity to density changes was defined by the variation in the residual errors from the linear regression line between time and density. RESULTS: The single-slice CT scanner was significantly less sensitive to density changes than MSCT scanners. Also, among MSCT scanners, small but significant differences were found when the standardized acquisition protocol was used. CONCLUSIONS: Considering the large sensitivity differences between single- and multislice CT scanners, we would recommended using MSCT scanners in clinical multicenter trials in emphysema. The protocol standardization of MSCT scanners can still be further improved.