Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiomediastinal and hilar contours are unremarkable . Retrocardiac opacification with faint air bronchograms may represent atelectasis versus aspiration in the setting of trauma with known T12 burst fracture . No other pulmonary opacifications identified . Known small pneumothorax identified on CT is not evident on radiograph . No pleural effusion or displaced rib fractures identified . Endotracheal tube and enteric catheter are well positioned .
    OUTPUT:
    
Known small pneumothorax identified on CT is not evident on radiograph . Retrocardiac opacification may represent atelectasis versus aspiration , new compared to same day CT .