Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours are normal . The pulmonary vasculature is normal . Minimal subsegmental atelectasis is demonstrated within the left lung base . No focal consolidation , pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities .
    OUTPUT:
    
Subsegmental atelectasis in the left lung base .