title: Variations in delineation of the obex by contrast radiography during percutaneous trigeminal tractotomy.
mesh_terms: D001933:Brain Stem / Q000000981:diagnostic imaging*; D014695:Cerebral Ventriculography; D003287:Contrast Media; D006801:Humans; D008722:Methods; D010148:Intractable Pain / Q000601:surgery*; D014277:Trigeminal Neuralgia / Q000601:surgery*
chemical_list: D003287:Contrast Media