Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . Patchy mid left lower lobe opacity is seen , raising concern for pneumonia . The right lung is clear . There is no pleural effusion or pneumothorax . The cardiac and mediastinal silhouettes are unremarkable . Note is made of a calcification at the aortic knob .
    OUTPUT:
    
Subtle left lower lobe opacity concerning for pneumonia . Recommend followup to resolution .