Clinical calculator summary
ACR Lung-RADS v2022
Clinical calculator summary
ACR Lung-RADS v2022
A standardized screening-LDCT assessment and management system based on the most suspicious finding.
Evidence-based context for fast calculator use
- Purpose:
- Reproduce the November 2022 ACR source table without defaulting a category or applying it outside screening.
- Population:
- People undergoing lung cancer screening with low-dose chest CT.
- Factors:
- Most suspicious finding, Baseline/new/growing or longitudinal status, Nodule attenuation and size branch, Airway or cystic pathway, Independent S modifier
- Reference:
- American College of Radiology. Lung-RADS v2022 Assessment Categories. November 2022.
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Lung-RADS™ v2022
Clinical Context & Background
This calculator implements the November 2022 ACR Lung-RADS assessment categories as an explicit source-table lookup for lung cancer screening low-dose CT. Select the single most suspicious finding and assess the independent S modifier. The form does not repeat the imaging-context question because this page is only for screening LDCT. Category 0 pathways, solid, part-solid, ground-glass, juxtapleural, airway, atypical-cyst, longitudinal, and 4X branches are represented separately.
The S modifier is independent: it records a clinically significant or potentially clinically significant non-lung-cancer finding but never changes the Lung-RADS category. Category 4X is a distinct category reserved for an underlying Category 3 or 4 finding with additional suspicious features; X is not a modifier.
Mean nodule diameter is the average of the long and short axes rounded to one decimal millimeter. Growth means an increase greater than 1.5 mm within 12 months; exactly 1.5 mm is not growth. A thin cyst wall is less than 2 mm and a thick wall is at least 2 mm. A qualifying juxtapleural nodule must be less than 10 mm, not 10 mm or less.
Lung-RADS applies to screening LDCT, not incidental or diagnostic CT and not known lung cancer. The source table cannot capture every imaging nuance, competing finding, comorbidity, or patient preference. An appropriately qualified radiologist must confirm the final category and management recommendation.
Formula Logic
ACR Lung-RADS v2022 source-table lookup: assign the category for the single most suspicious screening-LDCT finding; add S independently for a clinically significant non-lung-cancer finding.Reference Data
| Category | Assessment | Core management |
|---|---|---|
| 0 | Incomplete | Comparison/additional imaging or 1-3 month LDCT, as appropriate; then recategorize |
| 1 | Negative | 12-month screening LDCT |
| 2 | Benign appearance or behavior | 12-month screening LDCT |
| 3 | Probably benign | 6-month LDCT |
| 4A | Suspicious | 3-month LDCT; consider PET/CT when solid portion is at least 8 mm |
| 4B | Very suspicious | Diagnostic CT, PET/CT when appropriate, tissue sampling and/or clinical evaluation |
| 4X | Category 3 or 4 plus additional suspicious features | Tailor diagnostic evaluation to the underlying finding and added suspicious feature |
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
When To Use
- Use for lung cancer screening LDCT after reviewing the current examination and all available prior chest CT examinations.
- Select the single finding with the highest degree of suspicion and assess S separately.
How To Interpret
- Categories 1-2 are negative screens; Categories 3-4 are positive screens for audit purposes.
- Category 0 is temporary until comparison or short-interval reassessment allows a new category.
- Category 4X requires an underlying Category 3 or 4 finding plus an additional suspicious feature.
What To Do Next
- Follow the management paired with the exact source-table branch and measure follow-up timing from the current examination.
- Use specialist radiology and multidisciplinary judgment for Category 4 findings, competing abnormalities, comorbidity, patient preference, and diagnostic-test selection.
Limitations
- Screening LDCT only; not for incidental/diagnostic CT or known lung cancer.
- This selector assumes the user has already measured and characterized the finding correctly.
- The calculator does not replace review of the complete ACR table, notes, prior imaging, or individualized clinical assessment.
Validated Population
Lung cancer screening CT examinations addressed by ACR Lung-RADS v2022; this site verifies source-to-code implementation rather than independently validating clinical performance.
Stepped follow-up example
A non-airway Category 4A finding stable at 3 months becomes Category 3; if still stable at the next 6-month follow-up, it becomes Category 2.
Calculation verification history
Verified
Calculation verification history
Verified: Production browser revalidation
- Three source-backed Lung-RADS v2022 cases passed through visible production controls at Category 2, Category 4B with the independent S modifier, and Category 4X.
- The former valid-submission page crash was absent; no unexpected N/A, literal undefined value, stale control, or browser-console error was observed.
Case-level evidence is retained in validation/browser-revalidation/lung-rads-classification-system-2026-08-03.json.
: Local browser remediation verified; production retest pending
- Corrected both Lung-RADS result traces from unsupported `source-table lookup` to the registered `lookup` renderer method; the ACR source table was unchanged.
- Ten local visible-browser cases passed across Categories 0, 1, 2, 3, 4A, 4B, and 4X, the independent S modifier, an airway branch, required-field feedback, and reset/repeat behavior.
- The original production crash remains open until deployment and public revalidation.
Local diagnostic evidence is retained in validation/browser-production/lung-rads-classification-system.local-remediation.json.
: Production browser validation
- Ten source-backed cases were exercised on the public production route through visible browser controls; 1/10 case records passed their expected-versus-observed assertions across 13 visible submissions.
- Overall browser status: failed-calculation-ui-and-console. critical: Every valid tested Lung-RADS submission replaced the calculator with the browser error surface `This page couldn’t load`; no category, classification, management, trace, or result card survived. | medium: Production emitted minified React error #418 during route loads/reloads used by this run.
- Case-level inputs, expected and observed results, reset/repeat behavior, failure reproductions, and console evidence are retained in the production-browser evidence record.
Case-level production evidence is retained in validation/browser-production/lung-rads-classification-system.json.
: Input workflow simplified and revalidated
- Reduced the public form to result-, branch-, unit-, and applicability-changing inputs; removed or consolidated non-scoring, administrative, and duplicate questions.
- Preserved the verified calculation or report-interpretation logic, thresholds, model version, component logic, and supported result pathways behind strict deterministic adapters.
- Passed the calculator-specific regression audit, adapter-parity and malformed-input checks, the 144-calculator input-quality audit, and the 43-calculator entry-burden audit.
: Full validation test
- 720/720 source-branch, management, raw-boundary, longitudinal, special-pathway, malformed-input, UI, trace, wording, report, registry, and isolation checks passed.
- No registered master panel calculates Lung-RADS; no panel receives inherited verification.
: Calculation and input-contract correction
- Replaced the simplified 15-choice shortcut with 43 unique ACR v2022 source findings covering Categories 0, 1, 2, 3, 4A, 4B, and 4X, plus airway, cystic, juxtapleural, infectious/inflammatory, and stepped longitudinal pathways.
- Added the independent S modifier, strict screening-context gate, explicit assessment with no default, exact three-field validation, and raw >1.5 mm growth, <10 mm juxtapleural, 2 mm cyst-wall, and nodule-size boundaries.
Verification confirms the calculator implementation against the cited model; it is not independent clinical validation, regulatory approval, or medical advice.
Frequently Asked Questions
Can Lung-RADS be used for an incidental nodule?
No. This implementation returns Not applicable for incidental or diagnostic CT. Use an appropriate incidental-nodule pathway and specialist assessment.
Does the S modifier change the category?
No. S is recorded independently for a clinically significant non-lung-cancer finding and does not alter the Lung-RADS category.
Is 1.5 mm of growth enough to meet the Lung-RADS growth definition?
No. The v2022 definition requires an increase greater than 1.5 mm within 12 months.
Evidence-based oncology decision support. Verify with clinical guidelines.