Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Previously large left pleural effusion is substantially improved , now small . Small right pleural effusion is likely unchanged . No evidence of pneumothorax . There are foci of linear atelectasis in the mid and lower left lung . Mild cardiomegaly is unchanged cardiomediastinal hilar silhouettes are unremarkable . Median sternotomy wires are midline and intact .
    OUTPUT:
    
Small residual left pleural effusion . No pneumothorax .