Purpose To evaluate four-dimensional computed tomography (4D-CT)-derived pulmonary ventilation by comparing with 81mKr-gas ventilation (VRI). We also proposed two methods to improve the functional accuracy of 4D-CT ventilation images and evaluated these methods. Methods and materials Eleven lung cancer patients with 4D-CT and VRI were analyzed. Hounsfield unit-based (VHU) and a Jacobian-based (VJac) 4D-CT ventilation images were calculated. They were evaluated by voxel-by-voxel spearman's rank correlation coefficient (r) between 4D-CT ventilation and VRI images. After applying an averaging ventilation method and a slope calculating method, correlations were also calculated. Results 4D-CT ventilation showed the high correlation to VRI (r = 0.875 with VHU). An averaging method brought significantly higher (p = 0.012) correlations to nuclear medicine images with VHU. The improvement was not significant (p = 0.619) with VJac. Slope calculating method improved the correlation with VHU and slightly worsened the correlation with VJac. Conclusions The averaging method we proposed might be useful to improve 4D-CT ventilation images. We found good agreement between 4D-CT ventilation and nuclear medicine ventilation, indicating the high physiologic accuracy of 4D-CT ventilation.
- 4D-CT ventilation
- Functional imaging
- Kr-gas ventilation
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging