Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A subtle opacity in the left mid lung zone is likely due to superimposed chest wall structures and normal vessels . The lungs are otherwise clear . There is no pulmonary edema , pleural effusion , or pneumothorax . The cardiomediastinal silhouette is normal . The previously identified right rib fractures are not well visualized on today 's exam .
    OUTPUT:
    
No acute cardiopulmonary process .