Mn(Ⅱ)-Pectin As Oral Contrast Agent For Upper Abdominal MR Imaging: Experimental Study

[Objective] Mn(H)-Pectin was chosen to use as MR oral contrast agent.Test tube,animal experiment study were done to resolve a series of issues,including confecting,the most appropriate concentration and Biphasic contrast effect.The target was to offer a fundation that Mn(U)-Pectin can apply on the medicine practice.[Materials and Methods] Confecting Mn(II)-Pectin solution (concentration: 1.594mmol/L,pH=5.4) by Mn(II)-Pectin and MnCl2 4H2O and diluting this solution to eleven kind of concentration,all solution were preformed precontrast MR scan.In addition, other precontrast MR scan were preformed,including MnCl2 solution of different concentration containing the same quantity Mn2+ and pectin solution of different concentration containing the same quantity pectin,Mn(II)-Pectin solution of the same concentration (1.594mmol/L)and different pH(l-7), Mn(II)-Pectin solution and pectin solution and MnCl2 solution in the same pH(pH=5.4). SE T1WI, FRFSE T2WI sequences were performed.Signal intensity in all scan sequences was measured by ROI of 20 mm2.In the animal experiments,thirty rats were disparted to three groups at random.One group take Mn(II)-Pectin solution,other two groups take Mn(II)-Pectin solution with injecting scopolamine in the muscle and water,respectively.Precontrast and postcontrast MR scan were performed in all groups(injecting scopolamine in the muscle in the group of taking Mn(II)-Pectin solution with injecting scopolamine),which take differentimaging methods,including Axi SE T1WI, Axi FRFSE T2WI,Cor FRFSE T2WI,Axi BH FSPGR and Cor BH FSPGR sequences.The signal intensity of stomach and duodenum was measured.The enhanced ratio of stomach was computed.Showing of stomach wall,duodenum wall and viscera in the vicinity of gastrointestine were observed.[Results] In the test tube, Mn(H)-Pectin showed a good enhanced effect between 0.1328mmol/L~0.3985mmol/L on T1WI. The signal intensity of pectin and Mn(II)-Pectin is similar to the water and different from Mn(H)-Pectin solution. In the test tube,a stronger shorten T1 and T2 relaxation time effection showed on the imaging of Mn(II)-Pectin solution containing the same quantity Mn2+ than MnCl2 soIution.On the T1WI and PWI, Mn(II)-Pectin solution showed a similar change in the different pH value.On the T1WI, Mn(II)-Pectin had a stronger enhanced effect than pectin and MnCl2 solution. On the T2WI,the signal intensity of Mn(II) Pectin and MnCl2 solution neared to zero.On the animal experiment,the positive enhancement was observed on the T1WI and FSPGR.The negative enhancement was observed on the T2WI.A significant difference(P<0.05)had been observed between precontrast and postcontrast.After taking Mn(II)-Pectin solution,the signity intensity of stomach cavity had a significant difference(P<0.05) between Mn(II)-Pectin,Mn(n)-Pectin+654-2 and water on the T1WI. The signity intensity of stomach cavity had a significant difference(P<0.05) between Mn(II)-Pectin,Mn(II)-Pectin+654-2 and water on the T2WI. The enhanced ratio of stomach cavity had a significant difference(P<0.05) between Mn(n)-Pectin,Mn(II)-Pectin+654-2 and water on the T1WI.The enhanced ratio of stomach cavity had a significant difference(P<0.05) between Mn(H)-Pectin,Mn(II)-Pectin+654-2 and water on the T2WI. The enhanced ratio of stomach cavity had a significant difference(P<0.05) between Mn(II)-Pectin and Mn(II)-Pectin+654-2 on the FSPGR. Showing of stomach wall had no significant difference(P<0.05) between Mn(II)-Pectin and Mn(II)-Pectin+654-2 on the FSPGR. Showing of stomach wall had a significant difference(P<0.05) between Mn(n)-Pectin,pectin and water on theT2WL Showing of stomach wall had no significant difference(P<0.05) between Mn(II)-Pectin and pectin on the FSPGR. Showing of stomach wall had a significant difference(P<0.05) between pectin,Mn(II)-Pectin and pectin on the FSPGR. Showing of duodenum cavity had a significant difference(P<0.05) between precontrast and postcontrast on the Mn(II)-Pectin and pectin group. Showing of duodenum cavity had no significant difference(P<0.0...