Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There has been further aeration of the left lung base . Increased patchy opacification of the right lung base is noted . There is no pleural effusion or pneumothorax . The appearance of the mediastinum is unchanged with dense calcifications in the aortic arch . The cardiac silhouette remains mildly enlarged .
    OUTPUT:
    
Increased patchy opacity within the right lung base is likely atelectasis , although , a developing pneumonia can not be excluded .