Operative cholangiography offers a method of documenting the completeness of the choledochal examination at a time when the removal of a retained calculus can be accomplished at the initial surgery. No surgeon disputes the value of such a definitive diagnostic aid to manual exploration of the common bile duct. On the other hand, it is difficult to interpret films that fail to demonstrate contrast material entering the duodenum or films that exhibit a limbus configuration in the distal common bile duct resembling an unretrieved stone (Fig 1 and 2). The recent publication of Ginzburg et al1 and Senter and Berne2 have described such findings in relation to ductal spasm or edema. The interpretation and approach to such an apparent distal obstruction and to such quasi calculi on the operative and postoperative cholangiograms are frustrating problems which must distinguish between the normal roentgen appearance and pathologic conditions. Data obtained from