Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are normally expanded and clear . The cardiomediastinal silhouette , hilar contours , and pleural surfaces are normal . There is no pneumothorax . There is minimal blunting of the posterior costophrenic sulcus although it is unclear on which side .
    OUTPUT:
    
No definite evidence of pneumonia . There is mild blunting of the posterior costophrenic sulcus suggesting small pleural effusion .