Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lungs are hypoinflated with heterogeneous opacity of the left lung base , which likely represents atelectasis . There is no pleural effusion or pneumothorax . Cardiomediastinal silhouette is appropriate for size given portable technique and low lung volumes .
    OUTPUT:
    
Low lung volumes with heterogeneous left lower lobe opacity likely representing atelectasis .