Lung-RADS

Lung-RADSTM (or 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.

Category 0 (incomplete)
  • prior CT studies were performed, but are not available for comparison
  • lungs are incompletely imaged
Category 1 (negative, <1% chance of malignancy)
  • no lung nodules
  • lung nodule(s) with specific findings favouring benign nodule(s)
    • complete calcification
    • central calcification
    • popcorn calcification
    • calcification in concentric rings
    • fat-containing nodules
Category 2 (benign appearance, <1% chance of malignancy)
  • solid nodule(s)
    • <6 mm
    • new nodule <4 mm
  • subsolid nodule(s)
    • <6 mm on baseline screening
  • ground glass nodule(s)
    • <20 mm
    • ≥20 mm and unchanged or slowly growing
  • category 3 or 4 nodules that are unchanged for ≥3 months
Category 3 (probably benign, 1-2% chance of malignancy)
  • 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)
    • ≥20 mm on baseline CT or new
Category 4A (suspicious, 5-15% chance of malignancy)
  • 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
Category 4B (suspicious, >15% chance of malignancy)
  • solid nodule(s)
    • ≥15 mm
    • new or growing, and ≥8 mm
  • subsolid nodule(s)
    • solid component ≥8 mm
    • new or growing ≥4 mm solid component
Category 4X (suspicious, >15% chance of malignancy)
  • 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
Modified categories
  • [X]S (e.g. "3S") if there is a clinically significant or potentially significant non-lung cancer finding
  • [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 4: 

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

Category 5: 

  • 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)
  • nodule measurement should be in lung windows
  • nodule average diameter is rounded to the nearest whole number
  • 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

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Article Information

rID: 32681
System: Chest
Synonyms or Alternate Spellings:
  • Lung imaging reporting and data system

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