Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is normal . The aorta remains tortuous with mild calcification noted at the aortic arch . The mediastinal and hilar contours are otherwise within normal limits . The pulmonary vascularity is normal . Subsegmental atelectasis is demonstrated in the left lung base . No focal consolidation , pleural effusion or pneumothorax is identified . There are no acute osseous abnormalities .
    OUTPUT:
    
No radiographic evidence for pneumonia .