Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is mild basilar atelectasis . Subtle left mid - to - lower lung opacity may be due to atelectasis . The posteromedial aspect of the left third rib is not seen . No evidence of pneumothorax . No large pleural effusion is seen . The cardiac silhouette is top normal . The aorta is calcified and tortuous .
    OUTPUT:
    
Left mid-to - lower lung atelectasis without definite focal consolidation . No pneumothorax is seen . The posterior medial left third rib is not seen .