Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal and hilar contours are unchanged , with the cardiac silhouette size within normal limits . The pulmonary vascularity is not engorged . Elevation of the right hemidiaphragm is unchanged . Hazy opacity in the left lung base may reflect atelectasis , though infection can not be completely excluded . There is no pleural effusion or pneumothorax . There are degenerative changes in the thoracic spine as well as involving the right acromioclavicular joint .
    OUTPUT:
    
Hazy opacity in the left lung base , which may reflect atelectasis , though infection is not completely excluded .