<Dl> <Dt> Thickened alveolar septa </Dt> </Dl> <Dt> Thickened alveolar septa </Dt> <P> Acute: Pulmonary edema </P> <P> Chronic: Lymphangitic carcinomatosis, pulmonary alveolar proteinosis, sarcoidosis, pulmonary veno occlusive disease </P>

Extensive interstitial infiltrates are present. what does the term interstitial mean