Lung cancer screening CT — baseline or follow-up screen. Sizes are mean diameter (mean of long & short axis, each measured to one decimal point in mm, in any plane).
1 · Which exam is this?
Findings on a follow-up screen are categorized by behavior (new, growing, stable, resolved) as well as size.
2 · Category 0 or 1?
3 · Nodule type
4 · Size
5 · Category 4X & exam modifier (optional)
4X is a distinct Lung-RADS category, not a modifier (note 14): it applies to Category 3 or 4 nodules and is managed as 4B. S is the only exam modifier in v2022 — it may be added to categories 0–4 and does not change the lung-cancer follow-up.
Start: baseline or follow-up screen?
Lung-RADS v2022 categorization.
ACR Lung-RADS v2022, baseline and follow-up screens. Sizes are mean diameter; growth means an increase of > 1.5 mm in mean diameter within a 12-month interval (note 6). v2022 removed the per-category risk-of-malignancy percentages, so none are shown. Juxtapleural nodules use the < 10 mm cut-off printed in the official v2022 table; note that ACR's own Summary of Changes states ≤ 10 mm — this tool follows the table, so a nodule of exactly 10.0 mm is categorized as an ordinary solid nodule. Decision support only — not a substitute for the full criteria, the 16 table notes, or clinical judgment.
American College of Radiology. Lung-RADS v2022. acr.org/Lung-RADS.