Clinical perspectives of a sonographic secretin test.

The normal-sized pancreatic duct can be demonstrated today by sonography in about 90% of all persons examined. In healthy individuals intravenous bolus injection of secretin generally leads to a short-lasting distinct dilatation of Wirsung's duct being likewise visible on ultrasonography. Further investigations showed no or only a slight secretin-induced pancreatic duct dilatation in chronic pancreatitis, whereas patients with papillary or pancreatic duct stenosis had a marked and prolonged duct enlargement after stimulation. Different authors reported a high sensitivity and specificity of this sonographic secretin test in the diagnosis of chronic pancreatitis, even in early stages. In patients with pancreas divisum the secretin test result seems to be less uniform, a marked and prolonged duct enlargement after secretin stimulation, however, has been successfully used as a diagnostic criterion of accessory sphincter obstruction. Recently this test method has also been used to differentiate the etiology of cystic pancreatic lesions under observation by endoscopic ultrasonography. Since sonographic measurement of the pancreatic duct diameter before and after secretin stimulation is easy to perform with modern technical equipment, it could be a useful screening test for different diagnostic questions in pancreatic disease. Further investigations are needed for the evaluation of its reliability and standardization.