Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild cardiomegaly is present , decreased in size compared to the prior study . Mediastinal and hilar contours are within normal limits . The pulmonary vasculature is not engorged . There is minimal patchy retrocardiac opacity which may reflect atelectasis , however early infection is not excluded . No pleural effusion or pneumothorax is demonstrated . No acute osseous abnormalities seen .
    OUTPUT:
    
Minimal patchy retrocardiac opacity may reflect atelectasis , but an early infection can not be excluded in the correct clinical setting .