Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lower lung volumes are noted on the current exam . Increased perihilar opacities are now noted . Cardiomediastinal silhouette also is accentuated by lower lung volumes . No acute osseous abnormalities .
    OUTPUT:
    
Lower lung volumes . Perihilar opacities could be explained by atelectasis and crowding although superimposed vascular congestion or aspiration are difficult to exclude .