Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is s / p right upper lobectomy , better evaluated in prior chest CT . The lungs are well expanded , without focal opacities . Cardiomediastinal and hilar contours are unremarkable . Mild cardiomegaly is present . A slight prominence of the aortic knob represents an aortic nipple , likely from a traversing vessel , better seen in prior chest CT . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Mild cardiomegaly . No acute cardiopulmonary process .