Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac and hilar contours are unremarkable , with the heart size appearing top normal . Mild widening of the superior mediastinum may be due to mediastinal lipomatosis . Lung volumes are low with linear opacity demonstrated in the left lung base likely subsegmental atelectasis . No focal consolidation , pleural effusion or pneumothorax is present . No acute osseous abnormality is visualized .
    OUTPUT:
    
Probable subsegmental atelectasis the left lung base .