Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is of normal size . The aorta is tortuous and there is calcification of the aortic knob . Small linear opacity in the right lung base is compatible with atelectasis and / or chronic interstitial changes . The lungs are otherwise clear without focal or diffuse abnormality . No pleural effusion or pneumothorax . Osseous structures are unremarkable . No radiopaque foreign body .
    OUTPUT:
    
Small right lung base linear opacity , compatible with atelectasis and / or chronic interstitial changes . No pleural effusion or focal consolidation .