Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lungs are hyperinflated . Focal retrocardiac opacity is noted on the frontal view , not definitively localized on the lateral view . Lungs are otherwise clear . Borderline cardiomegaly with tortuosity of the thoracic aorta . No pulmonary edema . No pleural effusion . No pneumothorax .
    OUTPUT:
    
1 . Hyperinflation . 2 . Focal retrocardiac opacity . Possibilities include atelectasis , infection or mass lesion . Repeat after treatment for infection is suggested if this is clinically warranted . Otherwise cross - sectional imaging may help further characterize .