Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is retrocardiac opacity silhouetting the left hemidiaphragm similar to prior . Elsewhere , the lungs are clear noting that the left lung apex is obscured by patient 's chin . There is no overt edema . There is no large right - sided pleural effusion . The cardiomediastinal silhouette is grossly within normal limits .
    OUTPUT:
    
Retrocardiac opacity silhouetting the left hemidiaphragm . This could be combination of effusion , atelectasis and / or infection . Consider PA and lateral to further assess if desired .