Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are relatively low lung volumes . The cardiac silhouette is top - normal . Patchy left basilar opacity is seen , increased from prior . As well , there is a relative linear area of opacity at the more lateral left lung bases may be due to increased atelectasis . . The patchy opacities could be due to infection , aspiration , or atelectasis . There is subtle blunting of the left costophrenic angle , similar to prior , suggesting a small left pleural effusion . No pneumothorax .
    OUTPUT:
    
Patchy left basilar retrocardiac opacity appears increased from the prior study and may be due to infection , aspiration , and or atelectasis . More linear opacity in the lateral left lung base , increased from prior , may relate to atelectasis . Persistent blunting of the left costophrenic angle , suggest a small left pleural effusion .