Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are poorly defined opacities in the lower lobes , markedly improved since the recent CTA chest yesterday . There is no pneumothorax or pleural effusion . The cardiomediastinal silhouette is within normal limits . The underlying osseous structures are intact .
    OUTPUT:
    
Interval rapid improvement of the bilateral lower lobe opacities . Given the rapid improvement and distribution , aspiration is the likely diagnosis .