Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest . Endotracheal tube terminates 4 .3 cm above the carina . Right IJ central venous catheter terminates at the superior cavoatrial junction . Lumbar spine fusion construct is incompletely imaged . Heart size and cardiomediastinal contours are normal . Lung volumes are low , crowding of bronchovascular markings . Small retrocardiac opacities persist and may represent aspiration . No pleural effusion or pneumothorax . Interstitial edema has improved since the prior exam .
    OUTPUT:
    
Low lung volumes with interval improvement of interstitial edema . Small persistent retrocardiac opacities may represent aspiration .