Dynamic imaging of the pancreas using real-time endoscopic ultrasonography with secretin stimulation

Background: Obstructive disorders of the pancreas, including strictures, stones, sphincter of Oddi dysfunction, and pancreas divisum, are diagnostic and therapeutic challenges. Conventional extracorporeal ultrasound with secretin stimulation has been used as a noninvasive study to detect obstruction and predict outcome of therapy. Inconsistent results have been obtained because of the inherent limitations of standard ultrasonography. The aim of this study was to evaluate the behavior of the main pancreatic duct by endoscopic ultrasonography during secretin stimulation and to diagnose obstructive disorders of the pancreas. Methods: Secretin-stimulated endoscopic ultrasound (SSEUS, 1 IU/kg secretin) was performed in 20 control subjects (no pancreatic or biliary disease), 40 patients with symptomatic chronic pancreatitis, 40 patients with symptomatic pancreas divisum, 20 patients with suspected sphincter of Oddi dysfunction, and 20 patients with suspected occlusion of pancreatic duct stents. Ductal diameter was measured by endoscopic ultrasonography at baseline and at 1-minute intervals, after administration of secretin, for 15 minutes. A result was determined to be abnormal when a 1 mm or greater dilation of the pancreatic duct was observed from baseline after secretin administration. Results: Of the 40 patients with symptomatic chronic pancreatitis, SSEUS correctly predicted obstructive pathology (stones, strictures) in 12 of 13 patients (92%). Of the 40 patients with symptomatic pancreas divisum, 22 underwent stent therapy (16 of 22 with resolution of symptoms). SSEUS accurately predicted response to stent therapy in 13 patients (81%). Seven of twenty patients with suspected sphincter of Oddi dysfunction had abnormal sphincter manometry. SSEUS accurately predicted sphincter dysfunction in only 4 of 7 patients (57%). Finally, 20 patients with suspected occlusion of pancreatic duct stents were studied. Of the 14 stent occlusions confirmed at ERCP, SSEUS correctly predicted premature occlusion in 12 patients (86%). Conclusions: SSEUS appears to be a useful diagnostic modality in the evaluation of patients with suspected obstructive disorders of the pancreas and it can predict which patients may respond to endoscopic therapy.