Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right IJ catheter terminates at the caval atrial junction . An endotracheal tube is unchanged in position , terminating 6 .2 cm above the carina . The cardiac and mediastinal contours are unchanged . There is a trace left pleural effusion . A persistent left retrocardiac opacity likely reflects atelectasis . There is no pneumothorax or new consolidation .
    OUTPUT:
    
Persistent left retrocardiac opacity , likely atelectasis , though underlying consolidation can not be excluded . No new opacities . Unchanged small left pleural effusion .