Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are low . There is an opacity in the left lower lobe which may be atelectasis or pneumonia in the appropriate clinical setting . The cardiomediastinal hilar contours are normal . The pleural surfaces are normal . The catheter a left VP shunt is seen traversing the diaphragm however the ends are beyond the margin of this image . Stable advanced degenerative disease of the left shoulder with an unchanged osseous loose body in left axilla .
    OUTPUT:
    
Possible left lower lobe pneumonia in the appropriate clinical setting , less likely atelectasis .