What's the relationship between interstitial lung disease and pulmonary fibrosis?

Similiar: Interstitial lung disease is an "umbrella" term for many diseases; one of these disease is idiopathic pulmonary fibrosis or ipf.

Interchangeable: Pulmonary fibrosis is a pathologic description of interstitial lung disease which is a radiographic description of the disease. The terms are used interchangably but not all interstitial lung disease results in pulmonary fibrosis.

Same disease: Interstitial lung disease and idiopathic pulmonary fibrosis are different terms for the same disease. Fibrosis means scar tissue in lay terms. For unknown reasons fibrous tissue begins to replace normal lung causing difficulty breathing. At present there is no effective treatment although it is an intense area of research and many new drugs are being studied.