Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared with ___ , no definite change is detected . Again seen is a small posterior left pleural effusion , question on the left , with underlying collapse and / or consolidation , grossly similar to the prior study . Patchy opacities at both lung bases the blunting of the right costophrenic angle is also similar . Within the right and left upper and mid zones , no focal infiltrate is identified . There is mild cardiomegaly and aortic calcification , unchanged . No CHF . No pneumothorax detected . Hyperinflation , suggestive of background COPD .
    OUTPUT:
    
1 . Increased opacity in the lower lobe posteriorly , probably on the left , appears to represent a combination of a small amount of pleural fluid and patchy parenchymal opacity . The possibility of a pneumonic infiltrate and / or area of aspiration should be considered . 2 . Patchy opacities at the right an left lung bases are compatible with atelectasis and / or scarring and are not clearly changed . 3 . Mild cardiomegaly . No CHF or pneumothorax detected .