Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Bilateral predominantly perihilar heterogeneous opacities with subtle Kerley B lines are consistent with mild - to - moderate interstitial pulmonary edema . Mild cardiomegaly is not significantly changed allowing for differences in technique . The mediastinal contours are normal . There may be trace bilateral pleural effusions . There is no pneumothorax . The patient is status post midline sternotomy .
    OUTPUT:
    
1 . Mild - to - moderate interstitial pulmonary edema . 2 . Unchanged mild cardiomegaly . 3 . Possible tiny bilateral pleural effusions .