Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal , and hilar contours are unchanged and within normal limits . The pulmonary vascularity is normal . No focal consolidation , pleural effusion , or pneumothorax is seen . No acute osseous abnormality is visualized . In the left lower lung field , an oblong 9 - mm structure projects over the left eighth lateral rib , of unclear etiology , but appears unchanged compared to the prior study .
    OUTPUT:
    
No acute cardiopulmonary process .