Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single frontal supine image of the chest shows an unchanged retrocardiac linear opacity , which is most consistent with atelectasis . No new consolidation is identified . A trace left pleural effusion is present . The prior pulmonary vasculature congestion has improved . There is no pulmonary edema or pneumothorax . The cardiomediastinal silhouette is unremarkable . Mediastinal clips are noted . Sternotomy wires are intact . No free air is identified below the hemidiaphragms .
    OUTPUT:
    
1 . Trace left pleural effusion and stable retrocardiac atelectasis . 2 . No free air below the hemidiaphragms .