Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes remain low . Compared to prior , there has been mild interval improvement in pulmonary edema . Left retrocardiac opacity persists . Median sternotomy wires appear intact . There is no pneumothorax .
    OUTPUT:
    
Low lung volumes with mild interval improvement in pulmonary edema compared to prior . Otherwise , no relevant interval change .