Nodule Size (mm)*	Low-Risk Patient	High-Risk Patient
<4	No follow-up needed*	Follow up CT at 12 mo; if unchanged, no further follow-up
>4-6	Follow-up CT at 12 mo; if unchanged, no further follow-up	Initial follow-up CT at 6-12 mo, then at 18-24 mo if no change
>6-8	Initial follow-up CT at 6-12 mo, then at 18-24 mo if no change	Initial follow-up CT at 3-6 mo then at 9-12 and 24 mo if no change
>8	Follow-up CT at around 3, 9, and 24 mo, dynamic contrast-enhanced CT, PET, and/or biopsy	Same as for low-risk patient

"Note.-Newly detected indeterminate nodule in persons 35 years of age or
older.

* Average of length and width.

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

History of smoking or of other known risk factors.

The risk of malignancy in this category (<1%) is substantially less than
that in a baseline CT scan of an asymptomatic smoker.

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