Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild cardiomegaly is persistent compared to the prior exam . There is a subtle increase in opacity seen on the lateral view . The hilar and mediastinal contours are normal . There is no pleural effusion or pneumothorax . The visualized osseous structures are unremarkable .
    OUTPUT:
    
Subtle increase in opacity seen in the retrocardiac region on the lateral view , may be secondary to an infectious process , follow up is recommended after treatment .