Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A portable frontal chest radiograph demonstrates an unchanged cardiomediastinal silhouette , with interval mild decrease in a left pleural effusion . Left base atelectasis is likely related to a combination of pleural effusion and resultant atelectasis . There is no new focal consolidation , or pneumothorax . The visualized upper abdomen is unremarkable .
    OUTPUT:
    
Interval mild decrease in a left pleural effusion , with retrocardiac opacity likely atelectasis , although superimposed pneumonia can not be excluded in the right clinical setting .