Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The persistent left pleural effusion has decreased in size since the prior exam , now small to moderate . There is no focal consolidation or pneumothorax . The right lung is clear . Mediastinal clips and median sternotomy wires are intact . A clip in the left upper quadrant is noted .
    OUTPUT:
    
Persistent but decreased small - to - moderate left pleural effusion .