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

Objective: We focused on fibrosis within lung adenocarcinoma tumors in order to retrospectively analyze correlations with dual-phase contrast enhanced dynamic CT findings. Materials and methods: 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. Results: 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. Conclusions: 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.