Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest provided . Lung volumes are low limiting evaluation . There is subtle lower lung opacity which is most compatible with atelectasis though difficult to exclude a very early pneumonia . No large effusion or pneumothorax . No signs of congestion or edema . Cardiomediastinal silhouette is stable . Bony structures are intact . No free air below the right hemidiaphragm is seen .
    OUTPUT:
    
Mild bibasal opacities in the setting of low lung lung volumes likely reflects atelectasis . Difficult to exclude an early pneumonia .