Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is within normal limits and mediastinal contours demonstrate a tortuous aorta . The right lung is clear , and the left lung demonstrates a small persisting pleural effusion with minimal associated atelectasis . There is no pneumothorax . These findings are similar to prior exam .
    OUTPUT:
    
Persisting small left pleural effusion with associated atelectasis .