Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-upright radiograph of the chest demonstrates low lung volumes with resultant bronchovascular crowding . Dense retrocardiac opacity represents pleural effusion and atelectasis . Superimposed infection could be considered in the appropriate clinical setting . Fluid in the horizontal fissure on the right is stable . The right lung is relatively well aerated . The cardiomediastinal and hilar contours are unchanged . Two tubes course into the stomach and out of the field of view . Left - sided central line ends at the cavoatrial junction . No pneumothorax .
    OUTPUT:
    
Dense retrocardiac opacity represents pleural effusion and atelectasis , however superimposed infection could be considered in the appropriate clinical setting .