Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate a cardiomediastinal silhouette which is top normal in size to mildly enlarged . There is bibasilar atelectasis . Retrocardiac opacity likely corresponds to a large hiatal hernia with adjacent compressive atelectasis seen on the CT from the same day . There is no pleural effusion or pneumothorax . The visualized upper abdomen is unremarkable .
    OUTPUT:
    
1 . No pleural effusion . 2 . Retrocardiac opacity , likely corresponding to a large hiatal hernia with adjacent compressive atelectasis , as seen on CT from the same day . 3 . Mild cardiomegaly .