Can we Increase Detection of Duct Abnormalities by MRCP?
Administration of secretin improves noninvasive imaging of pancreatic duct abnormalities with higher levels of sensitivity than magnetic resonance cholangiopancreatography (MRCP), researchers report in the September issue of Gastroenterology.
Pancreatic imaging is an essential element in evaluation of patients with abdominal pain or suspected pancreatitis. MRCP allows physicians to visualize fluid in biliary and pancreatic ducts and outline their anatomy. It can also be used determine causes of bile duct obstruction, such as bile duct lithiasis, strictures, cholangiocarcinoma, and pancreatic adenocarcinoma. However, MRCP provides low-resolution images of pancreatic ducts, due to their small diameter.
MRCP’s resolution can be increased by intravenous administration of secretin, a 27-amino acid peptide hormone. Secretin stimulates release of pancreatic juice from acinar cells of the exocrine pancreas into the pancreatic ducts, increasing their size and structural delineation by MRCP.
However, no controlled multicenter studies have evaluated the effects of including secretin administration in the MRCP procedure.
Stuart Sherman et al. therefore performed a large, blinded, multicenter assessment of visualization of the hepatobiliary and pancreatic ducts, and detection of pancreatic duct abnormalities, in patients who underwent MRCP with and without administration of synthetic human secretin (RG1068).
In this phase 3 study, 258 patients with a history of acute or acute recurrent pancreatitis underwent a baseline MRCP, immediately followed by administration of RG1068 and repeat MRCP. Thirty days later, subjects underwent endoscopic retrograde cholangiopancreatography (ERCP), which was used as the standard, but is associated with many complications
Sherman et al. found that administration of RG1068 before MRCP significantly improved identification of pancreatic duct abnormalities, compared with MRCP alone.
Pancreatic duct abnormalities were observed in 60.2% of ERCP images. Radiologists were able to identify duct abnormalities in images collected by MRCP with RG1068 with significantly higher levels of sensitivity (and only slightly lower specificity) than those obtained from MRCP without RG1068.
RG1068 enhancement of MRCP was associated with greater duct segment visualization and allowed the researchers to identify patients who may not require therapeutic ERCP. Compared with baseline MRCP, RG1068-MRCP images increased the ability of radiologists to identify patients without pancreas divisum, duct disruption, duct stricture, or stenosis. Sherman et al. explain that accurate identification of patients without these abnormalities could reduce the number of unnecessary ERCP procedures.
Adverse events were reported in 38% of patients after MRCP and 68% after ERCP. Of the 55 patients who experienced a serious adverse event, 3 had events associated with MRCP and 52 had events associated with ERCP. The adverse events related to RG1068 were nausea, abdominal pain, and flushing; most were mild.
Sherman et al. conclude that inclusion of RG1068 in an MRCP examination improves several aspects of the imaging technique, increasing detection of specific duct lesions, enhancing visualization of duct segments, and providing reader confidence in identification of abnormalities.