Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are relatively low lung volumes and persistent elevation of the right hemidiaphragm . Reticular opacities at the lung bases correspond to chronic interstitial lung disease , pulmonary fibrosis as seen on prior studies including PET - CT from ___ however , relative airspace opacities projecting at the left lower lung in bilateral perihilar regions could be due to infection and / or pulmonary edema . No large pleural effusion is seen . There is no evidence of pneumothorax . The cardiac silhouette is not enlarged . Mediastinal contours are unremarkable .
    OUTPUT:
    
Known pulmonary fibrosis particularly at the lung bases , right greater than left . Relative airspace appearing opacities in the bilateral perihilar and left lung base regions are nonspecific , but could be due to infection or pulmonary edema .