The Study Of Both Magnetic Resonance Diffusion-weighted Imaging And Expression Of VEGF Compared With Pathology In Dog Model Of Liver Fibrosis

OBJECTIVE In our study, magnetic resonance diffusion-weighted imaging (DWI) and vascular endothelial growth factor (VEGF) immunohistochemical staining were underwent in dog model of liver fibrosis.The changes of them in different stage of liver fibrosis were analyzed.DWI and VEGF immunohistochemical staining results were compared with histopathological features to make further interpretations.As well as the correlations among them were analyzed,so as to choose method for assessing liver fibrosis reasonablely,to improve the diagnosis of hepatic fibrosis.METHODS 12 healthy male dogs were randomly divided into 2 groups, 10 dogs in experimental group,2 dogs in control group.0.125ml/kg saline were injected in peritoneal cavity twice a week in dogs of control group, while in experimental groups were injected 0.125ml/kg 50% of the carbon tetrachloride (CCL4) oil solution twice a week, and were received the high fat diet. The experimental group and control group were underwent MR examination and liver biopsy every 4 weeks respectively. All MR examinations were performed on a Siemens 1.5T unit, scanning sequences included:conventional T1WI, T2WI scan, then underwent DWI.Image postprocessing was performed on magnetic resonance image matching software, to obtain ADC value and EADC value.After each MR scan, biopsying of liver in dogs under the guiding of ultrasound, the liver tissue were underwent pathology routine HE staining, Masson staining and immunohistochemistry VEGF staining. The liver tissue samples were divided into 5 groups by the results of pathological stage, namely, S0-S4, the level of VEGF expression, the corresponding ADC values and EADC values were compared among different stages of liver fibrosis, analyzing the correlations among them.RESULT The experimental successfully received models of liver fibrosis:S0=12 cases, S1=9cases, S2=9cases, S3=10cases, S4=10cases. There Was a decreasing(increasing) trend in hepatic ADC(EADC) values with increasing degree of fibrosis. One-way ANOVA test was used to compare the difference of ADC(EADC) value among fibrosis stage. It showed there were significant differences among different fibrosis stages at ADC(EADC) value (P<0.01). The Spearman rank correlation test was used to assess the correlation both liver ADC values and EADC values and stage of fibrosis. There was negative(positive) correlation between stage of fibrosis and ADC(EADC) values of DWI images(P<0.05). VEGF expression increased with increaseing degrees of liver fibrosis.CONCLUSIONS An intraperitoneal injection of carbon tetrachloride in oil solution with the high fat diet in dogs can be established different stages of liver fibrosis. DWI imaging is a non-invasive technology and could be operated easily, and ADC value measurement has better reproducibility.DWI could provide a reference in early diagnosis,treatment and follow-ups for chronic liver disease. The value of ADC(EADC) can quantitatly analysis deferent degree hepatic fibrosis,the size of ADC(EADC) had negative(positive) correlation with degree of hepatic fibrosis.VEGF may play an important role in the process of liver fibrosis in chronic liver disease.