Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs of the chest demonstrate low lung volumes with resulting bronchovascular crowding . The cardiomediastinal and hilar contours are unchanged . The aorta is tortuous , and there is calcification of the aortic knob . The descending thoracic aorta appears enlarged as compared to prior radiographs , measuring 5 cm . There is no pneumothorax . There is a small left - sided pleural effusion . Increased opacification of the right base likely represents atelectasis , but superimposed infection can not be excluded .
    OUTPUT:
    
1 . Increased opacification of the right base likely represents atelectasis , however superimposed infection can not be excluded . 2 . The descending thoracic aorta appears possibly enlarged as compared to prior radiographs , measuring 5 cm .