The idiopathic interstitial pneumonias (IIPs) comprise a heterogenous group of disorders. 
They represent fundamental responses of the lung to injury and do not represent 'diseases' per se.
Idiopathic indicates unknown cause and interstitial pneumonia refers to involvement of the lung parenchyma by varying combinations of fibrosis and inflammation.
IIPs include seven entities listed in the table on the left in order of relative frequency.
These diseases have specific patterns of morphologic findings on HRCT and histology.
Before we call these findings idiopathic or cryptogenic, we should realise, that these patterns are also common findings in collagen vascular diseases (e.g., sclerodermia, rheumatoid arthritis) and drug-related lung diseases.
For instance in patients with rheumatoid arthritis findings of NSIP, UIP, OP and LIP have been reported. #Diagnosis #Radiology #Pulmonary #CTChest #Idiopathic #Interstitial #Pneumonia #IdiopathicInterstitialPneumonia #ILD #Findings #RadiologyAssistant