Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph obtained . There is retrocardiac opacity which could represent atelectasis or aspiration . In addition , there is subtle opacity obscuring the CP angle from the frontal view , which may represent tiny bilateral pleural effusions . A lateral view would aid in evaluation . The heart and mediastinal contours are normal . No signs of pneumomediastinum or pneumothorax . The bony structures are intact .
    OUTPUT:
    
Retrocardiac opacity concerning for atelectasis or aspiration . Possible tiny pleural effusions . Please refer to subsequent CT chest for further details .