Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs remain relatively hyperinflated . Bilateral pulmonary opacities has significantly improved in the interval ; however , subtle left base retrocardiac patchy opacities be due to atelectasis or aspiration . No definite pneumonia is identified . No pleural effusion or pneumothorax is seen . Saccular outpouchings along the descending aorta seen on prior chest CT from ___ better assessed on CT . The aortic knob appears larger on the current study as compared to ___ , however , this could relate to differences in patient position , the patient was rotated in the opposite direction ; the aortic knob appears more similar , if not smaller , compared to chest radiograph from ___ . . The bones are diffusely osteopenic . Thoracic DISH is noted .
    OUTPUT:
    
Subtle left base retrocardiac opacity may be due to atelectasis or aspiration . No definite focal consolidation of pneumonia is seen . Prominence of the aortic knob has increased since the prior study , but similar to ___ , and felt to at least in part be related to patient rotation .