Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is mildly enlarged . The aorta is tortuous and calcified . There is no pleural effusion or pneumothorax . There is vague low of posterior basilar opacity , present before , probably due to atelectasis , although somewhat more prominent . The lungs appear otherwise clear .
    OUTPUT:
    
Somewhat more prominent posterior basilar opacity but probably due to atelectasis or scarring . It may be appropriate , however , to repeat radiographs in follow - up in order to ensure resolution although pneumonia is doubtful .