Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy . There are low lung volumes . The patient 's body habitus also leads to underpenetration . The low lung volumes accentuate the bronchovascular markings . However , there may be mild pulmonary vascular congestion . No definite focal consolidation is seen . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is likely in part accentuated by the low lung volumes and AP technique .
    OUTPUT:
    
Low lung volumes , which accentuate the bronchovascular markings . However , there may be mild pulmonary vascular congestion .