Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right PICC terminates near the cavoatrial junction . There is complete opacification of the left hemithorax with leftward mediastinal shift , consistent with left lung collapse . A small component of a left pleural effusion is also likely present . There appears to be an abrupt cut - off of visualization of the left mainstem brochus . The right lung is grossly clear . Possible 4 mm nodular opacity is seen projecting over the right mid lung field . There is no pneumothorax . Pulmonary vascularity is normal .
    OUTPUT:
    
Left lung collapse with probable small component of left pleural effusion . Underlying pneumonia can not be excluded .