Table 1. Fleischner Society Guidelines for the Evaluation of Non-calcified Pulmonary Nodules Detected Incidentally by Nonscreening CT.

Nodule Size (mm) *	≤ 4	>4-6	>6-8	>8
Low- Risk Patient *	No follow-up needed. §	Repeat CT at 12 months. If unchanged, no further follow-up. °	Repeat CT at 6-12 months and 18-24 months if no change.	Repeat CT at 3, 9, and 24 months, dynamic contrast- enhanced CT, PET, and/or biopsy.
High- Risk Patient †	Repeat CT at 12 months. If no unchanged, no further follow-up. °	Repeat CT at 6-12 months and 18-24 months if no change. °	Repeat CT at 3-6 months and 9-12 and 24 months if no change.	Same as for low- risk patient.

^*Minimal or absent history of smoking and of other known risk factors.

^†History of smoking or of other known risk factors.

” Nonsolid (ground-glass) or partly solid nodules may require longer follow-up to exclude indolent adenocarcinoma.

Adapted from ²²