5
Indeterminate for UIP CT findings suggestive of an alternative diagnosis
Provisional low confidence
(51–69%)
Low to very low confidence
(≤50%)
• Diffuse distribution without
subpleural predominance
• Peribronchovascular predominant with subpleural
sparing (consider non-specific interstitial
pneumonia [NSIP])
• Peri-lymphatic distribution (consider sarcoidosis)
• Upper or mid lung (consider fibrotic
hypersensitivity pneumonitis [HP], connective
tissue disease-associated ILD [CTD-ILD],
sarcoidosis)
• Subpleural sparing (consider NSIP or smoking-
related interstitial pneumonia [IP])
• CT features of lung fibrosis
that do not suggest any
specific etiology
• Lung findings:
▶ Cysts (consider lymphangioleiomyomatosis
[LAM], pulmonary Langerhan's cell
histiocytosis [PLCH], lymphocytic interstitial
pneumonia [LIP], desquamative interstitial
pneumonia [DIP])
▶ Mosaic attenuation or 3-density sign (consider
HP)
▶ Predominant GGO (consider HP, smoking-
related disease, drug toxicity, acute exacerbation
of fibrosis)
▶ Profuse centrilobular micronodules (consider HP
or smoking-related disease)
▶ Nodules (consider sarcoidosis)
▶ Consolidation (consider organizing pneumonia,
etc.)
• Mediastinal findings:
▶ Pleural plaques (consider asbestosis)
▶ Dilated esophagus (consider connective tissue
disease [CTD])
