Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiomediastinal contours are within normal limits allowing for low lung volumes . New patchy and linear opacities in the left lower lobe are probably due to atelectasis in the setting of recent abdominal surgery . There is no substantial pleural effusion or pneumothorax .
    OUTPUT:
    
Patchy and linear left lower lobe opacities favor atelectasis over infectious pneumonia .