Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are normally expanded . A 12 mm nodular opacity along the left heart border may relate to a costochondral junction . Minimal right middle lobe atelectasis is chronic . Heart size is normal . There is no pleural effusion or pneumothorax . The included osseous structures are grossly intact . There is pectus excavatum .
    OUTPUT:
    
1 . No evidence of acute traumatic injury . 2 . 12 mm nodular opacity in the left lower lung may relate to a costochondral junction , however confirmation with anterior shallow oblique radiographs is recommended for confirmation .