Diagnosis of ILDs of unknown cause: UIP

  • UIP – Usual Interstitial Pneumonia – describes the typical histological and CT patterns occurring in IPF (Idiopathic Pulmonary Fibrosis).
  • This pattern is required for the diagnosis of IPF, when other known causes or features inconsistent with UIP can be ruled out.1,16
  • The most predominant UIP features to be found on HRCT in cases of IPF are reticular changes like honeycombing and traction bronchiectasis with the disease being most extensive in the lower lobes of the lung and having a peripheral distribution.16
  • Although honeycombing on HRCT is paramount for diagnosis, identification of this feature can be challenged through frequent disagreement among radiologists on their findings mainly due to other conditions that can mimic honeycombing, e.g. emphysema or traction bronchiectasis.16
Distribution and CT pattern of UIP (adapted from Mueller-Mang 2007)HRCT criteria for UIP pattern (ref 1)