Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient 's chin overlies the medial lung apices . The patient is also somewhat rotated . Given the above , there are low lung volumes with persistent elevation of the right hemidiaphragm . No large pleural effusion is seen . The cardiac and mediastinal silhouettes are stable . The patient is status post median sternotomy and cardiac valve replacement . There is left mid lung linear atelectasis / scarring . Mild to moderate interstitial edema is seen .
    OUTPUT:
    
Mild to moderate interstitial edema may be slightly exaggerated due to low lung volumes . Persistent elevation of the right hemidiaphragm .