Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear . Mediastinal and cardiac contours are within normal limits . There is a normal variant with the aortic knob nipple , compatible with an intercostal vein . There is no pneumothorax or pleural effusion .
    OUTPUT:
    
There are no significant cardiopulmonary abnormalities . The study is stable since ___ .