Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison ___ study the cardiomediastinal silhouette is stable . Left retrocardiac atelectasis is unchanged . Previously seen right basilar opacity likely represents vascular crowding secondary to low lung volume though superimposed pneumonia can not be excluded in the appropriate clinical setting . The upper lungs are clear . No pleural effusions or pneumothorax are seen . Again seen is a right PICC line with the catheter tip terminating at the distal SVC .
    OUTPUT:
    
Stable left retrocardiac atelectasis and no evidence of pulmonary edema . A superimposed pneumonia can not be excluded , in the right clinical setting , given the above findings .