Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right PICC terminates at the caval atrial junction . Lucency projecting over the left side of the mediastinum may be air within an incompletely collapsed left lower lobe instead , although it is difficult to exclude air within the mediastinum given the appearance . Atelectasis is also seen at the right lower lobe . Cardiac silhouette is unchanged . Apical emphysema , right greater than left , is again noted . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Lucency in the left mediastinum could reflect some air within a nearly collapsed left lower lobe , although pneumomediastinum would be difficult to exclude . CT may be obtained for further characterization if clinically indicated .