Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest . Lower lung volumes seen on the current exam . There is secondary crowding of the bronchovascular markings . Linear left retrocardiac opacity is seen . There is no effusion . The cardiomediastinal silhouette is stable . No acute osseous abnormality is identified .
    OUTPUT:
    
Lower lung volumes with crowding of the bronchovascular markings and left base opacity , potentially due to atelectasis , although infection is not entirely excluded .