Lung-RADS Calculator v. 2022

Lung Imaging Reporting and Data System (LUNG RADS ®)
A quality assurance tool designed by the American College of Radiology (ACR) to standardize lung cancer screening CT.

Please note: This calculator does not include the "S modifier". Per Lung-RADS® 2022, the S modifier can be added to any categories for clinically significant or potentially clinically significant findings unrelated to lung cancer. This modifier does not affect the follow-up recommendations.

Lung-RADS
Do any of the following apply to the exam?
* Note: Inflammatory/infectious findings may include segmental or lobar consolidation, multiple new nodules (more than six), large solid nodules (≥ 8 mm) appearing in a short interval, and new nodules in certain clinical contexts (eg, immunocompromised patient).
→ Estimated population prevalence: ~1%
→ Recommendation: Comparison to prior chest CT is required. Re-evaluate when the prior scan is available.
→ Estimated population prevalence: ~1%
→ Recommendation: Additional lung cancer screening CT imaging needed.
→ Estimated population prevalence: ~1%
→ Recommendation: Repeat low-dose chest CT in 1-3 month.

Note: Some findings indicative of an infectious or infectious process may not warrant short-term follow-up (eg, tree-in-bud nodules or new < 3 cm ground glass nodules). These nodules may be evaluated using existing size criteria with a Lung-RADS classification and management recommendation based on the most suspicious finding.
Do you want to evaluate nodules or cysts?

Pulmonary Cysts:

How is the cyst's wall?
How is the formation of the cyst?
Does the cyst show any growth?
Does the cyst show any growth?

Not categorized in LUNG-RADS

Thin-walled unilocular cysts are considered benign and are not scored in LUNG-RADS.
Note that fluid-containing cysts may represent an infectious process and are not classified in Lung-RADS unless other concerning features are identified.
If there are multiple cysts may indicate an alternative diagnosis such as Langerhans cell histiocytosis (LCH) or lymphangioleiomyomatosis (LAM) and are not classified in Lung-RADS unless other concerning features are identified.
→ Estimated population prevalence: ~9%
→ Recommendation: 6-month low-dose chest CT screening
→ Estimated population prevalence: ~4%
→ Recommendation: 3-month low-dose chest CT screening. PET/CT may be considered if there is a ≥ 8 mm solid nodule or solid component
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling
* PET/CT may be considered if there is a ≥ 8 mm (≥ 268 mm3) solid nodule or solid component

Pulmonary Nodules:

Does the nodule have any of the benign features below?
→ Estimated population prevalence: ~39%
→ Recommendation: 12-month low-dose chest CT screening
→ Estimated population prevalence: ~39%
→ Recommendation: 12-month low-dose chest CT screening

How is the composition of the nodule?
Does the nodule meet any of the following criteria?
Insert the short axis and long axis diameters to calculate the mean.

Error: Mean diameter of the solid component cannot be larger than the total mean diameter.

Is the nodule growing?
→ Estimated population prevalence: ~45%
→ Recommendation: 12-month low-dose chest CT screening
→ Estimated population prevalence: ~45%
→ Recommendation: 12-month low-dose chest CT screening
→ Estimated population prevalence: ~45%
→ Recommendation: 12-month low-dose chest CT screening
→ Estimated population prevalence: ~45%
→ Recommendation: 12-month low-dose chest CT screening
→ Estimated population prevalence: ~45%
→ Recommendation: 12-month low-dose chest CT screening
→ A ground-glass nodule (GGN) that demonstrates growth over multiple screening exams but does not meet the > 1.5 mm threshold increase in size for any 12-month interval may be classified as Lung-RADS 2 until the nodule meets findings criteria of another category, such as developing a solid component
→ Estimated population prevalence: ~45%
→ Recommendation: 12-month low-dose chest CT screening
→ Estimated population prevalence: ~45%
→ Recommendation: 12-month low-dose chest CT screening
→ Estimated population prevalence: ~45%
→ Recommendation: 12-month low-dose chest CT screening
→ Estimated population prevalence: ~9%
→ Recommendation: 6-month low-dose chest CT screening
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~9%
→ Recommendation: 6-month low-dose chest CT screening
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~9%
→ Recommendation: 6-month low-dose chest CT screening
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~9%
→ Recommendation: 6-month low-dose chest CT screening
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~9%
→ Recommendation: 6-month low-dose chest CT screening
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~4%
→ Recommendation: 3-month low-dose chest CT screening. PET/CT may be considered if there is a ≥ 8 mm solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~4%
→ Recommendation: 3-month low-dose chest CT screening. PET/CT may be considered if there is a ≥ 8 mm solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~4%
→ Recommendation: 3-month low-dose chest CT screening. PET/CT may be considered if there is a ≥ 8 mm solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~4%
→ Recommendation: 3-month low-dose chest CT screening. PET/CT may be considered if there is a ≥ 8 mm solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~4%
→ Recommendation: 3-month low-dose chest CT screening. PET/CT may be considered if there is a ≥ 8 mm solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~4%
→ Recommendation: 3-month low-dose chest CT screening. PET/CT may be considered if there is a ≥ 8 mm solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~4%
→ Recommendation: 3-month low-dose chest CT screening. PET/CT may be considered if there is a ≥ 8 mm solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling
* PET/CT may be considered if there is a ≥ 8 mm (≥ 268 mm3) solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Referral for further clinical evaluation
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling
* PET/CT may be considered if there is a ≥ 8 mm (≥ 268 mm3) solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling
* PET/CT may be considered if there is a ≥ 8 mm (≥ 268 mm3) solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling
* PET/CT may be considered if there is a ≥ 8 mm (≥ 268 mm3) solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling
* PET/CT may be considered if there is a ≥ 8 mm (≥ 268 mm3) solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling
* PET/CT may be considered if there is a ≥ 8 mm (≥ 268 mm3) solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling
* PET/CT may be considered if there is a ≥ 8 mm (≥ 268 mm3) solid nodule or solid component
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.
→ Estimated population prevalence: ~2%
→ Recommendation: Management depends on clinical evaluation, patient preference, and the probability of malignancy. Options are:
* Referral for further clinical evaluation, and/or:
* Diagnostic chest CT with or without contrast
* Tissue sampling Note: Slow-growing nodules may not have increased metabolic activity on PET/CT; therefore, biopsy, if feasible, or surgical evaluation may be the most appropriate management recommendation.
Attention: Any category 3 or 4 nodules with additional imaging findings that increase the suspicion of lung cancer  (such as spiculation, lymphadenopathy, frank metastatic disease, a GGN that doubles in size in 1 year, etc.), the score should be increased to Category 4X.

References:
  1. American College of Radiology. Lung CT Screening Reporting and Data System (Lung-RADS) v. 2022
  2. McKee, B. J., Regis, S. M., McKee, A. B., Flacke, S., & Wald, C. (2015). Performance of ACR Lung-RADS in a clinical CT lung screening program. Journal of the American College of Radiology : JACR, 12(3), 273–276. 

Click here to visit Lung-RADS 2022 page on ACR's website.

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More about the Lung-RADS Calculator

The Lung CT Screening Reporting and Data System (Lung-RADS), developed by the American College of Radiology (ACR), offers a standardized framework for interpreting and managing findings from low-dose computed tomography (LDCT) used in lung cancer screening. First introduced in 2014 and most recently updated in 2022, Lung-RADS provides structured categories to guide follow-up and management strategies based on nodule characteristics and changes over time. This Lung-RADS calculator applies the Lung-RADS version 2022 criteria to help radiologists and clinicians apply these guidelines more easily in routine practice.

Purpose and Scope of Lung-RADS

Lung-RADS is primarily intended for patients undergoing annual lung cancer screening who meet the eligibility criteria established by guidelines, such as age and smoking history. It is not intended for diagnostic CTs performed for symptoms or other clinical indications. By categorizing LDCT findings into a defined set of diagnostic categories, Lung-RADS seeks to minimize ambiguity, clarify risk estimates, and streamline communication with referring providers and patients.

Key Features of Lung-RADS Version 2022

The 2022 update introduced important refinements based on clinical feedback and research evidence. These include more detailed criteria for specific types of nodules and nuanced definitions to better stratify risk:

  • Airway-Centered Nodules: Now specifically addressed in the classification to reduce over-calling and clarify follow-up needs.
  • Atypical Pulmonary Cysts: Included with defined thresholds for concern, acknowledging their potential role in early lung cancer development.
  • Juxtapleural Nodules: Management guidance has been clarified for nodules abutting the pleura, which may have unique behavior and implications.
  • Stable or Decreasing Nodules: Growth criteria now include refined definitions for stability and regression, impacting long-term follow-up intervals.

Each of these changes reflects ongoing efforts to improve risk stratification and reduce unnecessary imaging while preserving early detection capabilities.

Lung-RADS Categories and Suggested Management

Lung-RADS categories range from 0 to 4X, reflecting the spectrum from incomplete findings to those requiring more intensive follow-up:

  • Category 1: Negative — continue annual screening.
  • Category 2: Benign appearance or behavior — continue annual screening.
  • Category 3: Probably benign — short-term LDCT follow-up recommended (e.g., 6 months).
  • Category 4A: Suspicious — LDCT or PET/CT in 3 months recommended; consider referral.
  • Category 4B/4X: Very suspicious — PET/CT, tissue sampling, or other diagnostic evaluation advised.

Recommendations are adjusted based on nodule type (solid, part-solid, ground-glass), size, and change from prior exams. The goal is to intervene appropriately when risk is high while avoiding overtreatment of benign findings.

Why Structured Reporting Matters in Lung Cancer Screening

The use of structured systems like Lung-RADS enhances consistency across radiologists, practices, and institutions. This harmonization is essential not only for accurate clinical care but also for registries, quality assurance, and outcome tracking. Standardization reduces variation in interpretation and ensures that recommendations are tied to established evidence and consensus practices.

Lung-RADS also supports patient-provider communication by assigning clear numeric categories with corresponding management pathways. This clarity helps set expectations and guides next steps, especially in shared decision-making discussions regarding lung cancer screening and follow-up plans.

Clinical Use and Limitations

While Lung-RADS is a valuable tool in the structured assessment of lung screening CTs, clinical judgment remains essential. Patient comorbidities, preferences, and risk factors should always be integrated into decision-making. Additionally, Lung-RADS is not intended to replace diagnostic evaluation for symptomatic patients or nodules discovered incidentally outside of a structured screening program.

This LUNG-rads calculator applies the Lung-RADS criteria to assist in classification and management planning, based on user-provided nodule characteristics and clinical context. Users are encouraged to review the most recent ACR documentation for comprehensive details and guidance.

Summary

Lung-RADS provides a systematic approach to evaluating LDCT findings in lung cancer screening, helping guide follow-up recommendations in a consistent and evidence-based manner. The 2022 updates build on this foundation by refining risk categories and clarifying criteria to address a broader range of nodule presentations. By incorporating Lung-RADS into screening workflows, clinicians can support efficient care pathways and contribute to the early detection and management of lung cancer.

Table of contents

ShowHide
  1. Lung-RADS Calculator v. 2022
    1. References:
  3. Related Calculators:
  4. More about the Lung-RADS Calculator
    1. Purpose and Scope of Lung-RADS
    2. Key Features of Lung-RADS Version 2022
    3. Lung-RADS Categories and Suggested Management
    4. Why Structured Reporting Matters in Lung Cancer Screening
    5. Clinical Use and Limitations
    6. Summary

2 Comments

  1. Avatar of Al Katz Al Katz says:
    November 7, 2023 at 9:17 am

    I could not resist commenting. Exceptionally well written!

    Reply
  2. Avatar of Sara R Sara R says:
    June 19, 2024 at 7:53 am

    Nicely done. So helpful

    Reply

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