Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The size of the left pneumothorax has decreased , but it is still present . There is also a small left pleural effusion which is slightly increased compared to prior . The left lung atelectasis has improved . The right lung remains essentially clear . There is mild cardiomegaly , and the mediastinal and hilar contours are normal .
    OUTPUT:
    
Interval decrease in size of left pneumothorax .