Lung-RADS

ACR Lung-RADS v2022 — lung cancer screening CT assessment category

Lung-RADS category

0 — Incomplete

1 — Negative

2 — Benign appearance or behaviour

3 — Probably benign

4A — Suspicious

4B — Very suspicious

4X — Very suspicious, with additional worrying features

Evidence

Original publication

Christensen J, Prosper AE, Wu CC, et al. ACR Lung-RADS v2022: Assessment Categories and Management Recommendations. Formalises the ACR Lung-RADS v2022 assessment categories used here (released by the ACR in November 2022), including the size thresholds, the approximate probability of malignancy per category, and the recommended follow-up interval.

Journal of the American College of Radiology, 2024

Open source

Guideline

Lung-RADS applies to low-dose CT lung cancer screening in the defined at-risk screening population, not to a CT done for another reason or in a patient with a known or suspected active cancer. Category 0 means the read is incomplete (e.g. a prior study is needed for comparison, part of the lung could not be evaluated, or findings suggest infection warranting a short-interval repeat scan) and is not itself a risk estimate. 4A, 4B, and 4X may add PET/CT when a solid component is ≥ 8 mm.

Last reviewed: 2026-09

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