Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The left lower lobe opacification has improved . No new consolidation . The pulmonary vasculature and hila are normal . No pleural effusion or pneumothorax . The cardiac silhouette is normal . The prominent aortic knob consistent with history of aortic aneurysm is unchanged .
    OUTPUT:
    
Improved left lower lobe pneumonia .