Which of the following contrast is used for esophageal perforation?
Ref. Grainger and Allison's Diagnostic Radiology. Page. 13
 
Non ionic water soluble contrast should be used in most cases of esophageal perforation such as Iohexol .
Water soluble contrast should be used instead of barium contrast to prevent barium related inflammation of the mediastinum if there is perforation .
Barium swallow
Gadolinium
Lohexol
Gastrograffin