Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest . On the lateral view , there is increased opacity in the retrocardiac clear space . There is no clear correlate for this finding on the frontal and it was not clearly identified on the prior exam . While this may be due to atelectasis , given that it is new from prior exam with similar inspiratory effort consolidation is also possible . There is no effusion . Cardiomediastinal silhouette is within normal limits . No acute osseous abnormality detected .
    OUTPUT:
    
New retrocardiac opacity on the lateral view potentially due to atelectasis however it was not seen on prior film with similar inspiratory effort , consolidation would also be possible . Please correlate clinically .