Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild enlargement of the cardiac silhouette is unchanged from ___ . Mediastinal silhouette and hilar contours are unremarkable and stable . There is a subtle right middle lobe opacity on frontal view without definite lateral correlate which likely represents atelectasis however infection can not be excluded . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Subtle right middle lobe opacity on frontal view without definite lateral correlate which likely represent atelectasis however infection can not be excluded in the appropriate clinical circumstance .