Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable AP radiograph through the chest was obtained . This demonstrates clear lungs bilaterally with no focal opacities suggestive of infective process . There has been interval removal of left - sided IJ . Persistent and unchanged prominent right superior mediastinum is identified . The heart appears within normal limits in size . There is no pleural effusion or pneumothorax . The right acromioclavicular joint appears slightly widened , stable since prior examination .
    OUTPUT:
    
No focal opacity identified convincing for pneumonia . Slightly prominent right superior mediastinum unchanged since prior examination dated ___ .