Lung-RADS Lung CT Screening Reporting and Data System

{
  "applicability": {
    "use_for": "Lung cancer screening CT examinations.",
    "exclude": [
      "incidental_nodule_outside_screening",
      "post_diagnosis_lung_cancer_staging"
    ],
    "incidental_alternative": "fleischner-2017"
  },
  "categories": [
    "0",
    "1",
    "2",
    "3",
    "4A",
    "4B",
    "4X",
    "S"
  ],
  "exam_rule": "Assign one numeric category from 0-4X according to the finding with the highest suspicion; S is an optional modifier, not a replacement category.",
  "measurement": {
    "mean_diameter": "Average long and short axes in any plane, report to 0.1 mm.",
    "volume_rounding": "nearest whole mm3",
    "growth": ">1.5 mm increase in mean diameter within 12 months",
    "threshold_crossing": "Reclassify when a nodule crosses a category size threshold even if it does not meet the growth definition."
  },
  "nodule_rules": {
    "solid": [
      {
        "outcome_code": "2",
        "when": [
          "baseline <6 mm",
          "new <4 mm"
        ]
      },
      {
        "outcome_code": "3",
        "when": [
          "baseline 6 to <8 mm",
          "new 4 to <6 mm"
        ]
      },
      {
        "outcome_code": "4A",
        "when": [
          "baseline 8 to <15 mm",
          "growing <8 mm",
          "new 6 to <8 mm"
        ]
      },
      {
        "outcome_code": "4B",
        "when": [
          "baseline >=15 mm",
          "new or growing >=8 mm",
          "slow growth over multiple exams without >1.5 mm growth in any 12-month interval"
        ]
      }
    ],
    "part_solid": [
      {
        "outcome_code": "2",
        "when": [
          "baseline total mean diameter <6 mm"
        ]
      },
      {
        "outcome_code": "3",
        "when": [
          "baseline total >=6 mm and solid component <6 mm",
          "new total <6 mm"
        ]
      },
      {
        "outcome_code": "4A",
        "when": [
          "baseline total >=6 mm and solid component 6 to <8 mm",
          "new or growing solid component <4 mm"
        ]
      },
      {
        "outcome_code": "4B",
        "when": [
          "baseline solid component >=8 mm",
          "new or growing solid component >=4 mm",
          "slow growth over multiple exams without >1.5 mm growth in any 12-month interval"
        ]
      }
    ],
    "ground_glass": [
      {
        "outcome_code": "2",
        "when": [
          "baseline, new, or growing <30 mm",
          ">=30 mm and stable or slowly growing"
        ]
      },
      {
        "outcome_code": "3",
        "when": [
          "baseline or new >=30 mm"
        ]
      },
      {
        "outcome_code": "4X",
        "when": [
          "doubles in size within 1 year or has another additional suspicious feature"
        ]
      }
    ],
    "juxtapleural": [
      {
        "outcome_code": "2",
        "when": [
          "<10 mm mean diameter",
          "smooth margins",
          "oval, lentiform, or triangular morphology"
        ]
      }
    ],
    "airway": [
      {
        "outcome_code": "2",
        "when": [
          "subsegmental",
          "segmental or proximal with internal air and no soft-tissue nodule"
        ]
      },
      {
        "outcome_code": "4A",
        "when": [
          "segmental or more proximal at baseline"
        ]
      },
      {
        "outcome_code": "4B",
        "when": [
          "segmental or more proximal and persistent at 3-month CT"
        ]
      }
    ],
    "atypical_pulmonary_cyst": [
      {
        "outcome_code": "3",
        "when": [
          "thick-walled cyst with growing cystic component"
        ]
      },
      {
        "outcome_code": "4A",
        "when": [
          "thick-walled cyst at baseline",
          "multilocular cyst at baseline",
          "cyst becomes multilocular"
        ]
      },
      {
        "outcome_code": "4B",
        "when": [
          "thick-walled cyst with increasing wall thickness or nodularity",
          "multilocular cyst with increased loculation or new/increasing opacity"
        ]
      }
    ]
  },
  "non_nodule_rules": [
    {
      "outcome_code": "0",
      "when": "prior CT is being obtained, lungs are incompletely evaluated, or indeterminate infection/inflammation warrants 1-3 month LDCT"
    },
    {
      "outcome_code": "1",
      "when": "no nodules or only nodules with definitely benign calcification/fat"
    },
    {
      "outcome_code": "4X",
      "when": "a category 3 or 4 nodule has added suspicious findings such as spiculation, lymphadenopathy, or metastatic disease"
    }
  ],
  "stepped_management": [
    {
      "from": "3",
      "if": "stable or decreased at 6-month LDCT",
      "to": "2",
      "next": "12-month screening LDCT from the current exam"
    },
    {
      "from": "4A",
      "if": "stable or decreased at 3-month LDCT",
      "to": "3",
      "next": "6-month LDCT from the current exam"
    },
    {
      "from": "3_after_4A",
      "if": "stable or decreased at the next 6-month LDCT",
      "to": "2",
      "next": "12-month screening LDCT from the current exam"
    }
  ],
  "modifier": {
    "outcome_code": "S",
    "apply_when": "clinically significant or potentially significant non-lung-cancer finding that is new or unexpectedly changing",
    "do_not_repeat_when": "the finding is already known and has been or is being evaluated"
  },
  "source_locator": "ACR Lung-RADS v2022 Assessment Categories table and Notes 1-16; v2022 Summary of Changes, stepped management section."
}