Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Mild bibasilar opacity is suggestive of atelectasis though difficult to exclude pneumonia . No free air below the right hemidiaphragm . The heart remains mildly enlarged . There is mild hilar congestion without frank edema . Mediastinal contour is normal . No pneumothorax or large effusion . Bony structures appear intact . No free air is seen below the right hemidiaphragm .
    OUTPUT:
    
Mild cardiomegaly with hilar congestion . Bibasilar opacities likely atelectasis , difficult to exclude pneumonia .