| Purpose: To establish a rabbit model infected by liver fluke disease,to explore the pathological changes of liver in rabbits infected with liver fluke disease before and after treatment and to investigate the value of Gd-EOB-DTPA–enhanced MRI for evaluating liver injury.Methods: An intragastric administration of Metacercariae was done to establish the rabbit model infected liver fluke disease.60 rabbits were divided into 3groups,which are the infected group,the treated group and the control group.Each group contains 20 rabbits.The rabbits in infected group and the treated group were given 100 metacercariae by lavage,and the control group was given normal saline.After 30 days,the infected group and the treated group were inspected for fecal worm eggs to confirm liver fluke disease infected.After 60 days of infection,these three groups of rabbits were examined for first time by magnetic resonance imaging.Siemens prisma 3.0T MRI and animal body coil were used to collect T1 WI and T2 WI images of the abdomen and multi-phase T1 mapping images before and 5-30 minutes after enhancement.Post-treatment images were performed on Syngo workstation and the average T1 relaxation time of the liver in each phase of T1 mapping was calculated.After the examination,the rabbits in the treated group were treated with Praziquantel to excrete parasite,and the infected group and the control group were fed accompanying with treated group.After the treatment,the rabbits fecal were examined in treated group to confirm whether the treatment was successful.After 60 days of treatment,rabbits in each subgroup underwent a second time magnetic resonance examination,after which all rabbits were executed.The liver tissue was pathologically sampled and stained with HE and Masson stain.T1 WI,T2WI and the multi-phase T1 mapping scan images before and after Gd-EOB-DTPA enhancement were observed and compared with pathological results.SPSS version 22 was used for statistical analysis.One-way analysis of variance was used to compare the difference between T1 relaxation time of each subgroup and the difference of liver tissue pathology score of each subgroup in the two magnetic resonance examinations.Least-Significant Difference and was used to make a pairwise comparison between each two subgroups.The paired t-test was used to compare the difference of T1 relaxation time before and after treatment in each subgroup.Spearman rank correlation was used to analyze the correlation between ishak score and image data.The area under the ROC curve was used to compare the diagnostic efficacy of each phase of T1 mapping on the cure of rabbit liver fluke.Results(1)49 rabbits finally completed the scheduled experimental plan: 16 in the infected group,15 in the treated group,and 18 in the control group.The detection rate of fecal worm eggs reached 100%--all rabbits infected with liver flukes successfully 30 days after infection by metacercaria.In the treated group,all fecal worm eggs examinations were negative after treatment with praziquantel,and the success rate of praziquantel treatment in the treated group was 100%.Each rabbit infected 15.25 ± 5.66 liver fluke on average;the collect rate of liver flukes is 15.25%.Rabbits in the infected group showed intrahepatic bile duct dilatation,bile duct wall thickening,bile duct epithelial hyperplasia,inflammatory cell infiltration and collagen deposition in the portal area.Rabbits in the treated group also showed bile duct expansion,thickening of the bile duct wall,and collagen deposition in the portal area,but to a lesser extent.There was no obvious bile duct epithelial hyperplasia.The pathological specimen of rabbit liver in the control group showed no abnormalities.Pathological specimens were scored according to ishak scoring criteria.The liver fibrosis score of the control group was 0.500±0.618,the infected group was 2.188±0.750,the treated group was 0.933 ± 0.458.After one-way analysis of variance,the difference in liver fibrosis scores among the three groups of rabbits was statistically significant,p<0.001(F = 32.788).After pairwise comparison,the control group Vs Infected group,treatment group vs infected group had statistical significant differences.The p-values were all less than 0.001,and the difference between the control group and the treatment group was not significant,p = 0.053.(2)Observation of liver MRI morphology showed that the intrahepatic bile duct dilation was seen in the infected group and the treated group.In the second time examination,the bile duct dilation in the infected group was worse than that of the first examination.The bile duct dilatation in the second examination of the treated group performed nearly the same as the first,and the control group’s intrahepatic bile duct examination showed no dilation.The rabbits in the control group had no dilation in the intrahepatic bile ducts.One-way analysis of variance was performed on the differences in T1 relaxation times of the three subgroups in the first magnetic resonance examination.The differences between the T1 relaxation times of the rabbit livers of the three subgroups were statistically significant from 5 minutes after enhancement to 25 minutes after enhancement Significantly,there is a statistical difference between the control group vs.infected group and the control group vs.treated group from 5 minutes after enhancement to 20 minutes after enhancement,but no statistical difference between the infected group and the treated group;T1mapping in 25 minutes shows that the difference between the control group and the infected group was statistically significant,and there was no statistically significant difference between the control group and the treated group,and between the infected group and the treated group.In the second magnetic resonance examination,the difference in T1 relaxation time between the three subgroups was analyzed by one-way analysis of variance.From pre-enhancement to 30 minutes after the enhancement,the difference in the T1 relaxation time of the three subgroups of rabbit livers was statistically significant.At 15 minutes,the difference between the three groups was most significant.After two-by-two comparisons after the event,there was a statistical difference between the infected group vs.the control group and the infected group vs the treated group from pre-enhancement to 30 minutes after the enhancement,but the control group vs the treated group showed no significant difference.Paired t-test was used to analyze the difference of T1 relaxation time between the two examinations in each rabbit of each group.In each phase of T1 mapping scan,the difference in the control group was not significant between the two examinations.In the infected group,there were significant differences between the two examinations in each T1 mapping scan.In treated group,there were statistical differences between the two examinations from pre-enhancement to 25 minutes after the enhancement,no significant difference in the 30-minute T1 mapping scans.Spearman rank correlation was used to analyze the correlation between T1 relaxation time and liver fibrosis score.In each phase of T1 mapping scans,both were significantly positively correlated,and the correlation was the strongest after 15 minutes of enhancement.The correlation coefficient was 0.697,p value = 0.000.The ROC curve was used to analyze the T1 relaxation time to assess whether the liver fluke infection was cured.The diagnostic efficacy was the strongest 15 minutes after the enhancement,and the area under the curve was 0.850.Conclusions(1)The rabbit model of liver fluke after 60 days of infection can be used to study the liver injury caused by fluke.(2)The T1 relaxation time of the liver had a correlation with the fibrosis score.As the degree of liver damage increases,the T1 relaxation time of the liver prolongs,and the liver injury of rabbits after the treatment of liver fluke is relieved,and the T1 relaxation time of the liver shortens.(3)T1 relaxation time can be used to assess whether the liver fluke infection was cured,and the diagnosis efficacy was the best at 15 minutes after enhancement. |
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