Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lungs are well expanded . Heart appears normal in size and configuration . Trachea is midline . Cardiomediastinal contours are unremarkable . Again an opacity is noted projecting over the anterior first rib on the right at the level of the sternal notch , which appears to be unchanged from the prior study . This likely represents changes associated with the empyema and the subsequent debridement . There is also minimal blunting of the right costophrenic angle possibly representing small effusion or atelectasis , which was also seen on the prior radiograph . No significant pleural effusions and no pneumothorax . Bony structures appear to be intact .
    OUTPUT:
    
No significant changes since the prior study ___ ___ .