Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Midline sternotomy wires are unchanged . The heart size is at the upper limits of normal . The mediastinal and hilar contours appear unremarkable . Opacity at the right lung base is compatible with components of atelectasis of the anterior - basal segment of the right lower lobe as well as a small right pleural effusion . Mild blunting of the left costophrenic angle suggests a trace amount of pleural fluid in that location . There is no pneumothorax . No displaced rib fracture is noted .
    OUTPUT:
    
Small right pleural effusion with right lower lobe anterior - basal segment collapse ; trace left pleural effusion .