Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Suboptimal comparison as no lateral view is obtained , however there is a retrocardiac opacity which may correlate with the opacity seen on the prior lateral view . No pleural effusion or pneumothorax identified . In the size the cardiomediastinal silhouette is within normal limits .
    OUTPUT:
    
A retrocardiac opacity may correlate with the abnormality seen on the prior radiograph 's lateral view , and in the correct clinical context may reflect pneumonia .