Characteristics of fibrotic-foci-like lung adenocarcinoma on 18F-FDG PET/computed tomography and HRCT.

PURPOSE: To assess the characteristics of fibrotic-foci-like lung adenocarcinoma on 18F-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) and high-resolution computed tomography (HRCT).

MATERIAL AND METHODS: This was a retrospective study with 20 cases in the fibrotic-foci-like lung adenocarcinoma group; the control group was old fibrotic-foci of the lung with 20 cases. The following 18F-FDG PET/CT and HRCT features were evaluated: the maximum standardized uptake value (SUVmax); the tumor-to-background ratios of SUVmax (TBRmax); the long-to-short diameter ratio (L/S); anatomic location; location type; internal characteristics; marginal characteristics and surrounding structures. In the fibrotic-foci-like lung adenocarcinoma group, a comparison of 18F-FDG uptake between the metastatic group (n = 10) and the non-metastatic group (n = 10) was performed. Finally, the comparison of diagnostic accuracy for fibrotic-foci-like lung adenocarcinoma between 18F-FDG PET/CT and HRCT was performed.

RESULTS: The SUVmax [2.6 (1.7-7.9) vs. 1.0 (0.7-1.4)], TBRmax [2.9 (2.1-9.9) vs. 1.3 (1.2- 1.7)], L/S [2.4 (1.7-3.8) vs. 4.0 (3.2-6.3)], ground-glass opacity (GGO) [13/20 (65.0%) vs. 4/20 (20.0%)], and vessel convergence [7/20 (35.0%) vs. 1/20 (5.0%)] were found to be statistically significant differences between the fibrotic-foci-like lung adenocarcinoma group and the old fibrotic-foci group (P < 0.05). SUVmax [7.9 (4.7-8.8) vs. 1.7 (1.2-2.2)] and TBRmax [9.9 (6.5-11.0) vs. 2.1 (1.6-2.9)] were found to be statistically significant differences between the metastatic group and the non-metastatic group (P < 0.05). 18F-FDG PET/CT showed the higher diagnostic accuracy for fibrotic-foci-like lung adenocarcinoma than HRCT [95.0% (19/20) vs. 65.0% (13/20), P < 0.05].

CONCLUSION: The specific characteristics of fibrotic-foci-like lung adenocarcinoma on 18F-FDG PET/CT and HRCT were high 18F-FDG uptake, GGO, and vessel convergence, which could be distinguished from old fibrotic-foci of the lung.