Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size and mediastinal contours are within normal limits . There is a small - to - moderate left - sided pleural effusion , similar to slightly increased to the prior exam with associated atelectasis . Medial left lung atelectasis is also present . There is no pneumothorax .
    OUTPUT:
    
Stable to slightly increased left pleural effusion with associated atelectasis .