Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes are low . The heart size is mildly enlarged , and slightly increased compared to the previous exam . The mediastinal contours are unchanged . Crowding of the bronchovascular structures is noted with mild pulmonary vascular congestion . A focal patchy opacity is seen within the right lower lobe , which could reflect an area of atelectasis or infection . No pleural effusion or pneumothorax is identified . There are no acute osseous abnormalities .
    OUTPUT:
    
Low lung volumes with mild pulmonary vascular congestion and patchy right lower lobe on opacity which may reflect atelectasis but pneumonia is not excluded .