Lung-RADS (Lung CT Screening Reporting and Data System) is a quality assurance tool published by the American College of Radiology (ACR) to standardize lung CT screening reporting and management recommendations. Version 2022 is the current edition.

Does this tool replace a radiologist?

No. This is a reference and educational tool only. All clinical decisions — including final Lung-RADS category assignment and patient management — must be made by a qualified radiologist reviewing the actual images.

What does the "S" modifier mean?

The "S" modifier is added to any Lung-RADS category when a clinically significant or potentially significant finding (other than a lung nodule) is identified on the CT, such as a pleural effusion or mediastinal adenopathy. This tool notes when S may apply but does not auto-assign it.

What is the 4X category?

Category 4X is assigned when a nodule has one or more additional suspicious features — such as spiculation, lymphadenopathy, or significant growth — that increase suspicion beyond what size alone would indicate. It carries a >15% estimated malignancy risk and typically warrants PET-CT or tissue sampling.

How are part-solid nodules classified?

For part-solid nodules, Lung-RADS uses the solid component diameter for risk stratification once a solid component is ≥6 mm. If the solid component is <6 mm, the overall nodule diameter drives category assignment.

What size thresholds does Lung-RADS 2022 use for solid nodules?

Solid nodules: <6 mm = category 2; 6–7 mm = category 3; ≥8 mm = category 4A; and modifiers push to 4B (≥15 mm or nodule with suspicious features) or 4X.

Lung-RADS Score Helper

Name: Lung-RADS Score Helper
Availability: InStock
Author: Nham Vu

Enter CT nodule findings to get the ACR Lung-RADS 2022 category and recommended follow-up interval.

Nodule Findings

Nodule morphology

Solid Part-solid (mixed GGO + solid) Ground-glass only (non-solid)

Mean nodule diameter (mm)

Additional suspicious features

Spiculation or lobulation Documented interval growth (>1.5 mm increase in mean diameter) New or growing solid component in previously pure GGO Suspicious mediastinal / hilar lymphadenopathy

Enter nodule findings on the left and click Calculate

Summary

Enter CT nodule findings to get the ACR Lung-RADS 2022 category and recommended follow-up interval.

How it works

Select whether the nodule is solid, part-solid, or ground-glass (pure non-solid).
Enter the nodule's average diameter in millimeters.
For part-solid nodules, enter the solid component diameter separately.
Check any suspicious features (spiculation, location, growth) that apply.
The tool applies ACR Lung-RADS 2022 decision logic and returns the category and follow-up recommendation.

Use cases

Radiologists double-checking Lung-RADS category assignment at the reading workstation.
Pulmonologists reviewing lung screening reports with patients.
Medical students and residents learning Lung-RADS 2022 decision trees.
Clinicians coordinating follow-up scheduling for incidental CT nodule findings.
Quality assurance review of lung screening program reports.
Nursing staff preparing patient education materials on lung nodule monitoring.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu