Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Large blebs are again noted in the upper lungs . Subtle opacities again noted in the lower lungs which appear slightly improved from the prior exam and likely represent stigmata of chronic aspiration . Difficult to exclude a subtle pneumonic process . No large effusion . Cardiomediastinal silhouette is stable . No definite signs of pneumothorax . Bony structures are intact .
    OUTPUT:
    
Slight improvement in lower lung opacities , likely reflect stigmata of chronic aspiration .