Lung-RADS

Last revised by Dr Jeremy Jones on 03 May 2022

Lung-RADS (Lung Imaging Reporting and Data System), is a classification proposed to aid with findings in low-dose CT screening exams for lung cancer. The goal of the classification system is to standardize follow-up and management decisions. The system is similar to the Fleischner criteria but designed for the subset of patients intended for low-dose screening studies.

  • prior CT studies were performed, but are not available for comparison
  • lungs are incompletely imaged
  • no lung nodules
  • lung nodule(s) with specific findings favoring benign nodule(s)
    • complete calcification
    • central calcification
    • popcorn calcification
    • calcification in concentric rings
    • fat-containing nodules
  • solid nodule(s)
    • <6 mm at baseline
    • new nodule <4 mm
  • <10 mm perifissural nodules with characteristic (solid nodules with smooth margins, an oval, lentiform or triangular shape) appearance (version 1.1 addition)
  • subsolid nodule(s)
    • <6 mm on baseline screening
  • ground glass nodule(s)
    • <30 mm (version 1.1 change previously 20 mm)
    • ≥30 mm and unchanged or slowly growing (version 1.1 change previously 20 mm)
  • category 3 or 4 nodules that are unchanged for ≥3 months
  • solid nodule(s)
    • ≥6 mm to <8 mm at baseline
    • new nodule 4 mm to <6 mm
  • subsolid nodule(s)
    • ≥6 mm total diameter with solid component <6 mm
    • new <6 mm total diameter
  • ground glass nodule(s)
    • ≥30 mm on baseline CT or new (version 1.1 change previously 20 mm)
  • solid nodule(s)
    • ≥8 mm to <15 mm at baseline
    • growing nodule(s) <8 mm
    • new nodule 6 mm to <8 mm
  • subsolid nodule(s)
    • ≥6 mm total diameter with solid component ≥6 mm to <8 mm
    • new or growing <4 mm solid component
  • endobronchial nodule
  • solid nodule(s)
    • ≥ 15 mm at baseline
    • new or growing, and ≥8 mm
  • subsolid nodule(s)
    • solid component ≥8 mm
    • new or growing ≥4 mm solid component
  • for new large nodules that develop on an annual repeat screening CT, a 1 month LDCT may be recommended to address potentially infectious or inflammatory conditions. (version 1.1 addition)
  • category 3 or 4 nodules with additional features or imaging findings that increase the suspicion of malignancy
  • includes:
    • spiculation
    • ground glass nodule(s) that double in size in 1 year
    • enlarged regional lymph nodes
  • for new large nodules that develop on an annual repeat screening CT, a 1 month LDCT may be recommended to address potentially infectious or inflammatory conditions. (version 1.1 addition)
  • [X]S (e.g. "3S") if there is a clinically significant or potentially significant non-lung cancer finding
  • (version 1.1 removal): [X]C (e.g. "3C") for a patient with a prior diagnosis of lung cancer who returns to screening

Category 0:

  • comparison with prior studies before assignment of Lung-RADS classification

Category 1: 

  • continue annual screening with LDCT

Category 2: 

  • continue annual screening with LDCT

Category 3: 

  • 6-month follow-up with LDCT

Category 4A: 

  • 3-month follow-up with LDCT
  • PET-CT may be used if there is a ≥8 mm solid component

Category 4B and 4X: 

  • chest CT with or without contrast, as appropriate
  • PET-CT and/or tissue sampling depending on the probability of malignancy and comorbidities (PET-CT if solid component ≥8 mm)
  • for new large nodules that develop on an annual repeat screening CT, a 1 month LDCT may be recommended to address potentially infectious or inflammatory conditions. (version 1.1 addition)
  • nodule measurement should be in lung windows
  • to calculate nodule mean diameter, measure both the long and short axis to one decimal point, and report mean nodule diameter to one decimal point. [previously recommended rounding to nearest whole number version 1.0.]
  • only a single measurement is necessary for round nodules
  • "growth" is an increase in size of ≥1.5 mm
  • assignment of a Lung-RADS status is based on the most suspicious nodule
  • category 4B management is based on multiple factors including overall patient status and patient preference
  • solid nodules with smooth margins, an oval, lentiform or triangular shape, and maximum diameter less than 10 mm (perifissural nodules) should be classified as category 2. (version 1.1 addition)
  • for category x, the Lung-RADS is rendered as "Lung-RADS category x" or "Lung-RADS x".

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