Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is no radiographic evidence of acute , displaced rib fracture or pneumothorax . Exam is somewhat limited by overlying external monitoring leads which obscure fine detail . A vague 1 .9 cm round opacity overlying the left second anterior rib may potentially be due to a structure external to the patient and is not well localized on the lateral view . Heart size is normal . Aorta is tortuous . Lungs are clear except for relatively symmetrical biapical scarring .
    OUTPUT:
    
1 . No radiographic evidence of acute , displaced rib fracture or pneumothorax . 2 . 1 .9 cm opacity in left upper hemi thorax , likely due to a structure external to the patient , although a discrete pulmonary nodule is not excluded .