The Study Of Pancreatic Exocrine Function Assessed By Secretin Stimulated Magnetic Resonance Imaging

Objective:To evaluate the healthy pancreatic exocrine function by Secretin Stimulat ed Magnetic Resonance Cholangiopancreatography(S-MRCP) technique and Diffusion Weighted Imaging(DWI) technique.Method:Objects to be checked were30healthy volunteers, All of the volunteers used extracorporeal calibration device for30minutes’scan. MRCP was performed with the HASTE technique, and DWI was performed with the echo planar imaging (EPI) sequence and b value of0,400s/mm2.Consider MRCP,T2coronal scan and DWI sequence as comparison before secretin injection, and then programmed a MRCP sequence with calibration device as mask. Every minute after injecting secretin, MRCP and T2coronal scan were continuously carried out until the10th minute. Then repeat the methods listed above every two minutes up to the30th minute. DWI sequences were programmed every five minutes from the10th minute to30th, and the quantity of secretin was8mcg.Through Siemens Singo magnetic resonance postprocessing system collecting and handling images, contrast and analyze them. Calculate the mean and standard deviation between groups’ data, compare the changes before and after secretin injection, and go on relevant statistical analysis.Result: After secretin injection we found that the healthy were persistently secreting pancreatic juice. After injecting secretin healthy pancreatic ducts began to expand, at the(2.7±0.9)minute to the maximum degree and then turned to the base line. Compare pancreatic duct caliber before injecting secretin and the maximum of pancreatic duct caliber after that. By using the Paired samples T test,the head, body and the tail of pancreatic duct comparisons had statistical difference (P<0.05). The peak time of secreted pancreatic juice was between (24.9±4.4) minutes and the maximal secretory capacity was (91.2±43.2)ml. The time of the first maximum secretion increment and that of the second emerged respectively between (3.7±2.4)minutes and between (15.4±5.7) minutes. Maximum secretion increments twice were separately (12.7±5.1) ml and (14.5±10.2)ml. The pancreatic juice-time curve indicated that the secretion of pancreatic juice in the first15minutes and the time after secretin injection became linear regression relationship. The Pearson correlation analysis test (p<0.01) showed significant correlation. We found that the less than30minutes’secretory secretin volume and time-secretion trend graph could be simulated by square curve equation, and at the25.64minute, a turning time point, the parabola began descending. Filling degree of pancreatic juice in duodenum reached the level3degree at the (10.8±2.4) minute, and after10minutes to the total length, including proximal and distal jejunum. The ADC value, before injection:[(2.39±0.26)×10-3mm2/s],after that:10minutes[(2.42±0.31)×10-3mm2/s],15minutes [(2.38±0.25)×10-3mm2/s],20minutes [(2.40±0.22)×10-3mm2/s],25minutes [(2.44±0.18)×10-3mm2/s],30minutes [(2.50±0.13)×10-3mm2/s]. The Paired samples T test (P>0.05) showed that ADC values had no statistical difference before and after secretin injection. The rADC value, before injection:[(1.15±0.13)×10-3mm2/s],after that:10minutest (1.19±0.15) x10-3mm2/s],15minutes [(1.18±0.20)×10-3mm2/s],20minutes [1.17±0.88)×10-3mm2/s],25minutes [(1.14±0.10)×10-3mm2/s],30minutes [(1.22±0.27)×10-3mm2/s]. The Paired samples T test (P>0.05) showed that rADC values had no statistical difference before and after secretin injection.Conclusion:Secretin Stimulated MRCP technique and DWI technique can evaluate the pancreatic exocrine function of healthy people; After secretin injection, pancreatic juice will increase to the peak volume and gradually return to the base state;Before and after secretin injection there are no changes in pancreatic ADC values and rADC values.