Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes cause bronchovascular crowding . Allowing for this , there is likely mild pulmonary vascular congestion without frank pulmonary edema . Retrocardiac opacification is likely due to atelectasis , however an early consolidation is difficult to exclude . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
1 . Low lung volumes . 2 . Retrocardiac opacification is likely due to atelectasis , however an early consolidation is difficult to exclude . 3 . Mild pulmonary vascular congestion without frank edema .