title: Letter: Spasm and operative cholangiography.
mesh_terms: D014670:Ampulla of Vater; D002758:Cholangiography / Q000379:methods*; D003949:Diagnostic Techniques, Surgical; D006801:Humans; D005996:Nitroglycerin / Q000494:pharmacology; D013035:Spasm / Q000175:diagnosis*; D009803:Sphincter of Oddi
chemical_list: D005996:Nitroglycerin