Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A 4 - mm subpleural nodular opacity at the right lung apex could be focal scarring versus a tiny pulmonary nodule . The lungs are otherwise clear . The heart size is normal . The mediastinal contours are normal . There are no pleural effusions . No pneumothorax is seen .
    OUTPUT:
    
1 . No acute cardiac or pulmonary process . 2 . 4 - mm nodular opacity at the right lung apex , non-specific in nature . Recommended correlation to PPD skin test .