Use in screening only. Follow the cited outcome for management; category timing is measured from the exam currently being interpreted.
{
"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."
}