Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette size is mildly enlarged . The aorta is tortuous , with atherosclerotic calcifications noted at the aortic knob and unchanged dilatation of the ascending aorta . The pulmonary vasculature is normal . Apart from minimal atelectasis at the lung bases , the remainder of the lungs are clear . No pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities identified including no displaced rib fractures .
    OUTPUT:
    
Mild bibasilar atelectasis . No fracture identified . If there is continued concern for rib fracture , a dedicated rib series is suggested .