Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes are seen . There is dense retrocardiac opacity asymmetric when compared to the right . Tracheostomy tube is in place . Right - sided central venous catheter tip projects over the lower right atrium . Cardiac size is difficult to assess given low lung volumes and left basilar opacity .
    OUTPUT:
    
Low lung volumes with crowding of the bronchovascular structures with superimposed left basilar opacity which could represent a combination of effusion , consolidation or atelectasis .