Diagnostic HRCT criteria for usual interstitial pneumonia (UIP) pattern - Fleischner society guideline (2018)

In 2018, the Fleischner Society provided updated diagnostic HRCT criteria for usual interstitial pneumonia (UIP) pattern based on literature review and the expert opinion of members. As a part of this white paper, diagnostic HRCT criteria for usual interstitial pneumonia (UIP) pattern were updated. 

The 2018 revised diagnostic HRCT criteria for usual interstitial pneumonia (UIP) pattern published by the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association has converged to a similar categorization of the HRCT findings into four groups.  

Typical UIP CT pattern

• distribution

  • basal predominant (occasionally diffuse)

  • subpleural predominant

  • often heterogeneous

• features

  • honeycombing

  • reticulation with peripheral bronchiectasis or bronchiolectasis 

  • absence of features suggesting an alternative diagnosis 

• the presence of this pattern, in the correct clinical setting, permits a confident diagnosis of IPF (idiopathic pulmonary fibrosis)

• if the clinical setting is equivocal for IPF, lung biopsy and further review in a multidisciplinary meeting are recommended 

Probable UIP CT pattern

• distribution 

  • heterogenous basal

  • subpleural predominance

• features

  • reticulation with peripheral bronchiectasis or bronchiolectasis 

  • absence of features suggesting an alternative diagnosis 

  • honeycombing is absent

• the presence of this pattern, in the correct clinical setting, permits a confident diagnosis of IPF (idiopathic pulmonary fibrosis) 

• if the clinical setting is equivocal for IPF, lung biopsy and further review in a multidisciplinary meeting are recommended 

CT pattern indeterminate for UIP 

• distribution 

  • variable or diffuse 

• features

  • evidence of fibrosis with some inconspicuous features suggestive of a non-UIP pattern 

• diagnosis of IPF cannot be reached and lung biopsy and further review in a multidisciplinary meeting are recommended 

CT features most consistent with non-IPF diagnosis 

• distribution

  • upper or mid lung predominant fibrosis 

  • peribronchovascular predominance with subpleural sparing

• features, any of the following:

  • predominant consolidation

  • predominant ground glass opacity without acute exacerbation 

  • extensive mosaic attention with extensive sharply defined lobular air trapping on expiration

  • nodules 

  • cysts

• diagnosis of IPF cannot be reached and lung biopsy and further review in a multidisciplinary meeting are recommended 

The paper also states that all patients with an IPF diagnosis should have it reviewed at periodic intervals.