Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . Mediastinal and hilar contours are unchanged with atherosclerotic calcifications of the aortic knob noted . There is mild pulmonary vascular congestion . Low lung volumes are noted . Patchy opacities in the lung bases may be due to the atelectasis in the setting of low lung volumes though infection or aspiration can not be completely excluded . Small right pleural effusion is decreased in size compared to the previous study . No pneumothorax is identified .
    OUTPUT:
    
Low lung volumes with patchy bibasilar opacities , potentially atelectasis but infection or aspiration is not excluded . Mild pulmonary vascular congestion . Trace right pleural effusion , decreased in size compared to the previous study .