Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to prior radiographs , lung volumes are low . Retrocardiac opacification is likely atelectasis . There is no focal consolidation or pleural effusion . The cardiomediastinal silhouette is unremarkable . No acute skeletal abnormalities .
    OUTPUT:
    
No focal infiltrate . Retrocardiac opacity is likely atelectasis at the left lower lobe .