Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . Mediastinal and hilar contours are within limits . Pulmonary vasculature is not engorged . 18 mm nodule within the right lower lobe was better visualized on the previous PET - CT . Lungs are otherwise clear . No focal consolidation pleural effusion pneumothorax is present . Mild degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
No acute cardiopulmonary process . Re - demonstration of 18 mm right lower lobe pulmonary nodule , better assessed on the previous PET - CT . Follow up chest CT is suggested for improved comparison , if not done recently .