Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) represents one of the most common chronic interstitial lung diseases. Usual interstitial pneumonia (UIP) is the pathologic diagnosis of IPF and can be diagnosed when honeycombing is present with a basilar and peripheral predominance and findings not typical of UIP are absent. In the current era, when a diagnosis of UIP is made with confidence on HRCT, biopsy can be avoided. Yet, one must be familiar with mimics of UIP/IPF (most notably pulmonary edema superimposed on emphysema) to avoid confusion misdiagnosis. Radiologists must also be familiar with potential complications of UIP including progression, infection, accelerated fibrosis (which can be lethal) and primary lung cancer (which has an increased incidence in UIP).