Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Borderline enlargement of the cardiac silhouette is unchanged . The aorta is mildly tortuous and demonstrates atherosclerotic calcifications at the knob . The mediastinal and hilar contours are unremarkable . The pulmonary vasculature appears normal . Apart from subsegmental atelectasis in the left lung base , the lungs are clear . No pleural effusion or pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Mild left basilar atelectasis . Otherwise , no acute cardiopulmonary abnormality .