Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to the most recent exam , lung volumes are slightly lower . Diffuse airspace opacity has diminished , particularly in the right mid lung . In addition , there is improvement in diffuse interstitial edema . Right pleural effusion is small . The cardiomediastinal silhouette is unchanged . Calcification of the aortic arch is present with tortuosity of the descending aorta is noted . There is no pneumothorax .
    OUTPUT:
    
Improving airspace opacity and edema .