CT characteristics of resolving ground-glass opacities in a lung cancer screening programme

Purpose

This study aimed at evaluating the computed tomography (CT) characteristics of resolving localized ground-glass opacities (GGOs) in a screening programme for lung cancer.

Material and methods

280 patients at high-risk for lung cancer (221 men, 59 women; mean age, 58.6 years), divided into four groups (lung cancer history (n = 83), head and neck cancer history (n = 63), symptomatic (n = 88) and asymptomatic (n = 46) cigarette smokers), were included in a prospective trial with annual low-dose CT for lung cancer screening. We retrospectively reviewed all localized GGOs, analyzed the CT characteristics on initial CT scans and changes during follow-up (median 29.1 months). Variables associated with resolution of GGOs were tested using chi-square or Mann-Whitney tests.

Results

A total of 75 GGOs were detected in 37 patients; 54.7% were present at baseline and 45.3% appeared on annual CT. During follow-up, 56.2% persisted and 43.8% disappeared. The resolving localized GGOs were significantly more often lobular GGOs (p = 0.006), polygonal in shape (p = 0.02), mixed (p = 0.003) and larger (p < 0.0001) than non-resolving localized GGOs.

Conclusion

Localized GGOs are frequent and many disappeared on follow-up. CT characteristics of resolving GGOs show significant differences compared to persistent ones. This study emphasizes the importance of short-term CT follow-up in subjects with localized GGOs.