Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable chest radiograph demonstrates low lung volumes and bibasilar opacity . A right subclavian central venous catheter tip terminates in the right atrium . The cardiac silhouette is top normal , the mediastinal contours are notable for ectasia of the aortic arch . The pulmonary vasculature is normal .
    OUTPUT:
    
1 . Low lung volumes and bibasilar atelectasis could hide pneumonia . 2 . Right subclavian central venous catheter tip projecting over the right atrium .