Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . The aorta is mildly tortuous . Mediastinal and hilar contours are otherwise unremarkable . There is no pulmonary vascular congestion . Subsegmental atelectasis is noted at the lung bases . No focal consolidation , pleural effusion or pneumothorax is demonstrated . No acute osseous abnormality is identified .
    OUTPUT:
    
Subsegmental bibasilar atelectasis . No evidence for pneumonia .