35 and above, pure ground glass nodule, multiple nodules, largest nodule 6 mm or larger, < 6 months.

ACR Fleischner Society recommendations (MacMahon, et al. Radiology 2017; 284(1): 228-43) suggest the following: Initial follow-up chest CT at 3-6 months to confirm persistence. If stable, follow-up chest CT every 2 years until 5 years.