Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are reduced . Heart size is mildly enlarged but unchanged . Mediastinal contours are stable . There is mild pulmonary vascular congestion . Assessment of the lung bases is limited due to poor inspiratory volumes , with a retrocardiac opacity possibly reflecting atelectasis . Infection or aspiration is not excluded . No pneumothorax is detected . Assessment for a pleural effusion is limited on these views as the left costophrenic angle is excluded .
    OUTPUT:
    
Limited study . Low lung volumes limit assessment of the lung bases . Retrocardiac opacity could reflect atelectasis but infection or aspiration can not be excluded . Mild pulmonary vascular congestion .