Objective:To explore the assessment value of multimodal imaging technique for the hepatic fibrosis(HF)of rats.Methods:Forty-eight SD rats were selected,and they were divided into control group,M1 model group,M2 model group and M3 model group according to random number table,with 12 rats in each group.The three model groups were induced by combination method of carbon tetrachloride(CCl4)plus ethanol to establish HF model.At the 4th,6th and 8th week of modelling,the M1 model group underwent ultrasound examination,and the M2 model group underwent examination of magnetic resonance,and the M3 model group adopted the examinations of conventional ultrasound,ultrasound elastography and dynamically contrast enhanced magnetic resonance imaging(DCE-MRI).The rats of control group were randomly divided into three subgroups,with four rats in each subgroup,which were controlled with the rats in the M1,M2 and M3 groups,respectively.At the end of the imaging examinations,the HE staining were conducted on the liver tissues so as to observe the HF degree of rats.The conventional ultrasound was used to observe the morphology of the rat liver,and to measure the inner diameter of the main trunk of the portal vein.colour Doppler ultrasound was used to measure the blood flow velocity of portal vein.Ultrasound elastography was used to observe the color distribution of liver parenchymal stiffness,and to measure the elasticity value of liver parenchyma.The initial area under curve(iAUC)of the receiver operating characteristic(ROC)was adopted to analyze the volume transit constant(Ktrans),rate constant(Kep)and extravascular extracellular space volume fraction(Ve)of the hemodynamic parameters in enhanced magnetic resonance examination.Results:The conventional ultrasound showed there was no abnormal changes in the livers of rats in control group,and the morphology of the liver of M1 group occurred changes.Ultrasound elastography showed that the elasticity values of the liver of rats in M1 group appeared upward trend with the aggravation of the HF degree than control group.Conventional MRI of group M2 showed that the liver morphology was normal in the control group,and the changes of the liver morphologies of rats in M2 group at the 6th and 8th week post modeling were more obvious than that at the 4th week post modeling.The ROC curve analysis of DCE-MRI results showed that Ktrans and Ve had higher diagnostic efficacy for HF,and their iAUC values were>0.9.The results of intergroup comparison of rats among M1 model group,M2 model group and M3 model group indicated that the sensitivity,accuracy,positive predictive value and negative predictive value of multimodal imaging technique were significantly higher than those of single examination in diagnosing HF at early stage of rats,and the differences were statistically significant(x2=0.634,0.644,0.621,0.543,P<0.05),respectively.HE staining results showed that the liver tissues of the rats in the model groups appeared fibroplasia of different degrees.Conclusion:Multimodal imaging technique can be used as an effective test method of evaluating hepatic fibrosis.
Hepatic fibrosisUltrasound elastographyDynamically contrast enhanced magnetic resonance imaging(DCE-MRI)
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