A comparison of a new non-ionic (metrizamide) and a dissociable (metrizoate) contrast medium in endoscopic retrograde pancreatography (ERP).

Endoscopic retrograde pancreatography (ERP) was performed on 12 patients with a non-ionic contrast medium (metrizamide) and a traditional dissociable medium (metrizoate). All patients were examined with both media at an interval of one week. The study was based on double blind and a cross-over randomization. There was a significantly lower rise in serum amylase 2 (p = 0.05), 4 (p = 0.04), and 6 hours (p = 0.03) after the examination using the non-ionic contrast medium than after using a dissociable one. The pain during contrast filling of the pancreas was significantly lower (p = 0.015) when using metrizamide than when using metrizoate. All, except one patient, preferred the examination with the non-ionic contrast medium (p = 0.0002). A positive correlation was found between pain and degree of pancreatic filling when using the dissociable medium (r = 0.77). Such a correlation could not be detected following the non-ionic contrast medium (r = 0.009). There was a positive correlation between rise in serum amylase and degree of pancreatic filling with both contrast media. The coefficient of correlation was lower after metrizamide (r = 0.21) than after metrizoate (r = 0.56). It is concluded that a non-ionic contrast medium in this study was better tolerated than a dissociable medium, and that metrizamide was more suitable for endoscopic retrograde pancreatography than the traditional hypertonic contrast medium.