This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oesophagus, Subject name: Surgery
[{'content': 'Dye used in diagnosis of early & late suspected esophageal perforation includes \nSelect and explain. \nA. Iohexol, B. Barium sulphate, C. Gadolinium, D. Iodine dye', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) IohexolCareful endoscopic assessment at the end of any procedure combined with chest X-ray will identify many cases of perforations immediately. If not recognised immediately, early & late suspected perforations should be assessed by a water soluble contrast like Iohexol.[?]Esophageal Perforation:Diagnosis:CXR-Classic Features:Mediastinal Air with or without subcutaneous air. Left-sided pleural effusion; PneumothoraxWidened mediastinum.Radiographic evidence may not be present in early phase of disease.Gastrografin esophagogram (Gold Standard); EndoscopyManagement: Early diagnosis is key; Broad spectrum antibiotics; Surgical Repair CONTRAST MEDIA USED IN RADIOLOGICAL DIAGNOSIS* Dye used in contrast enhanced magnetic resonance angiography (MRA)Gadolinium (GDPA)* Dye used in contrast enhanced MRIGadoliniumCT Scan, DSAMetrizamide (Water soluble organic iodide media)* Myelography & VentriculographyOmnipaque (contains Iohexol)* Dye used in oral cholecystographylopanoic acid (Telepaque); Sodium lopodate (Biloptin)* Dye used in ChromocystoscopyIndigocamine* Dye used in BronchographyDionosil (Propylidone)* Dye used in SialographyNeohydiol (Lipiodol)* Dye used in UrethrographyConray 280 (contains-Meglumine iothalamate) Umbradil viscos* Dye used in FetographyEthkxhl* Dye used in Intravenous cholangiographyBiligraffin(contains Meglumine loglycamate)* Dye used in Splenoportography75% sodium metrizoate (Triozil)* Dye used in ArthrographyCon-ray 280* Dye used in GynaecographyCO2 * Dye used in Angiocardiography coronary arteriographyNiopam 370* Dye used in HysterosalpingographyCon-ray 280 (Meglumine Iothalamate); Urograffm 280* Dye used in Oesophagography (Barium swallow)Gastrografin - Barium 150%w/v.* Dye used in LymphangiographyMethylene blue or Lipiodol ultrafluid* Dye used in IVPCon ray 420 Hypaque* Dye used in for intestinal obstruction / perforationGastrograffin', 'role': 'assistant'}]