Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . No prior . There is a small region of opacity in the retrosternal clear space on the lateral view , not definitively seen on the frontal but potentially in the right mid lung . Elsewhere , lungs are clear and the costophrenic angles are sharp . Cardiomediastinal silhouette is within normal limits . Median sternotomy wires and mediastinal clips are noted . Atherosclerotic calcifications noted within the thoracic aorta . Osseous and soft tissue structures are otherwise unremarkable .
    OUTPUT:
    
Small opacity in the retrosternal clear space on the lateral view , potentially localizing to the right on the frontal . This may represent focal infection in the proper clinical setting . With lack of suggestive history , CT should be considerd to further evaluate .