Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette size is normal . The aorta is mildly tortuous . The mediastinal and hilar contours are otherwise unremarkable . The pulmonary vasculature is normal . Linear opacities within the left lung base likely reflect subsegmental atelectasis . No focal consolidation , pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities .
    OUTPUT:
    
Minimal left basilar subsegmental atelectasis . No radiographic evidence for pneumonia .