Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded and clear . Increased hyperdensity of the left lung base is due to overlapping soft tissues . No pleural effusion or pneumothorax . Heart size , mediastinal contour and hila are unremarkable . Mildly prominent aorta measuring 4 cm throughout its thoracic course . No focal aneurysmal dilatation . Aortic arch calcifications noted . Limited assessment of the upper abdomen is unremarkable . Osseous structures are notable for kyphosis , with degenerative changes of the thoracolumbar spine .
    OUTPUT:
    
1 . Normal chest radiograph . 2 . Mildly prominent aorta measuring 4 cm throughout its thoracic course . No focal aneurysmal dilatation .