Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest . On the current exam , there is no evidence of confluent consolidation . Linear opacities at the left lung base most suggestive of scarring . Icreased interstitial markings are seen compatible chronic underlying lung disease , not significantly changed since ___ . Trace bilateral effusions . Cardiac silhouette is enlarged and also notable for a prosthetic aortic valve . No acute osseous abnormality detected .
    OUTPUT:
    
Chronic lung disease without definite superimposed acute process .