Relationship between the extraction of MRCP images of the pancreatic pipe and the circadian rhythm of human pancreas

Abstract

With the advancement of magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP) can now be used to obtain high-resolution images of the pancreatic and biliary ducts. MRCP, which is an imaging method based on hydrographs, is less invasive and has gained clinical significance. It uses heavily T2-weighted MRI pulse sequences that show high-intensity signals in fluids within the biliary and pancreatic ducts. Therefore, its capability to extract images of the pancreatic duct is affected by the quantity of fluids within the pancreatic duct, which may vary depending on the circadian rhythm. The circadian rhythm of human exocrine pancreatic secretion was observed even without food intake (Wakasugi et al., 1987). We investigated the effect of the circadian rhythm of the pancreatic secretion on the image extraction capability of MRCP. On the basis of a report, we took MRCP images of the pancreatic duct of healthy volunteers three times a day: once between 6:00 and 8:00 (medium pancreatic secretion), once between 12:00 and 14:00 (peak secretion), and once between 18:00 and 22:00 (minimum secretion). We evaluated the MRCP images visually and in terms of the signal intensity. From the results of this study, however, we were not able to establish an association between the image extraction capability of MRCP and the circadian rhythms in human exocrine pancreatic secretion as pointed by Wakasugi et al.