Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-upright radiograph of the chest demonstrates low lung volumes which results in bronchovascular crowding . There has a been interval decrease in size of the right - sided pleural effusion . There is atelectasis at the right base . Persistent retrocardiac opacity is present . Patient is status post tracheostomy , which ends 4 .8 cm from the carina . Cardiomediastinal and hilar contours are unchanged .
    OUTPUT:
    
1 . Persistent retrocardiac opacity . 2 . Interval decrease in size of the right - sided pleural effusion .