Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . Patchy retrocardiac opacity seen on the lateral view , not seen on the frontal view , could be due to underlying infection , atelectasis , or aspiration . No pleural effusion or pneumothorax . The cardiac and mediastinal silhouettes are stable .
    OUTPUT:
    
Questionable retrocardiac opacity seen in the lateral view , not substantiated on the frontal view , could be due to overlapping structures , atelectasis ; however , consolidation from infection or aspiration not excluded .