Correlation between dual-phase dynamic multi-detector CT findings and fibrosis within lung adenocarcinoma tumors

Abstract

We focused on fibrosis within lung adenocarcinoma tumors in order to retrospectively analyze correlations with dual-phase contrast enhanced dynamic CT findings. We evaluated 89 patients with stage I lung adenocarcinoma who underwent dynamic CT scans (80-96 mL of contrast material, 2.5-3 mL/s injection) and tumor resections. Attenuation values of both the early phase (21-37 s after injection) and the delay phase (91-95 s) of enhanced CT minus the baseline plain CT attenuation were calculated as ΔEarly and ΔDelay. An early enhancement ratio was defined as ΔEarly/ΔDelay×100. These enhancement patterns were compared with patient and tumor characteristics, including scar grades that were the degrees of fibrosis within tumors evaluated semi-quantitatively by pathologists. From multivariate analysis, only the tumor scar grade showed significant correlations with ΔEarly (p<0.001) and the early enhancement ratio (p<0.001). For ΔEarly and the early enhancement ratio, there were significant differences among 4 groups based on tumor scar grades (p=0.003 and p=0.006, respectively); a higher scar grade tumor tended to show lower enhancement at the early phase. There was a significant negative correlation between the amount of fibrosis and the enhancement grade at the early phase of contrast enhanced dynamic CT in stage I lung adenocarcinoma. Dynamic CT findings could be modified by the degree of fibrosis within a lung tumor.