Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Bilateral low lung volumes . Convexity of the upper right mediastinal contour suggest dilatation or tortuosity of the ascending aorta . The lungs are clear without focal consolidation . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
No evidence of a pneumonia . Convexity of the right upper mediastinal contours suggest dilatation or tortuosity of the ascending aorta , uncertain if changed from previous .