Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable view of the chest is compared to previous exam from ___ . Compared to prior , there has been no significant interval change . Again seen is a retrocardiac opacity which silhouettes the descending thoracic aorta . This could potentially be due to a hiatal hernia ; however , PA and lateral views suggested to confirm as mentioned on prior . Elsewhere , the lungs remain clear . Cardiomediastinal silhouette is normal . Osseous and soft tissue structures grossly unremarkable .
    OUTPUT:
    
No definite acute cardiopulmonary process . Retrocardiac opacity , likely hiatal hernia ; however , PA and lateral suggested to confirm .