Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes persist . Compared to the prior study from ___ , there has been interval decrease in opacity in the left mid lung zone and possibly slight decreased in the right mid lung however , similar to slightly increased in comparison with ___ . There is a possible trace right pleural effusion . Cardiac silhouette is top - normal . Mediastinal contours are stable .
    OUTPUT:
    
Bilateral heterogeneous lung opacities have slightly improved as compared to the prior study .