Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . The aortic knob is calcified . Mediastinal and hilar contours are unremarkable . The pulmonary vasculature is normal . Minimal streaky left basilar opacity likely reflects atelectasis . No focal consolidation , pleural effusion or pneumothorax is visualized . There are no acute osseous abnormalities .
    OUTPUT:
    
Left basilar atelectasis .