Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours are normal . The pulmonary vascularity is normal . Small left pleural effusion is noted with mild left basilar opacification likely reflecting atelectasis . The right lung is clear without evidence of a right - sided pleural effusion . No pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Small left pleural effusion with associated left lower lobe compressive atelectasis .