A Preliminary Experimental Study Of Liver Fibrosis With Magnetic Resonance Diffusion-weighted Imaging In Rabbit Model

Hepatic fibrosis is a common clinical disease, but has no specific clinical symptoms, hepatic cirrhosis is irreversible and causes serious consequences. Liver biopsy diagnosis of hepatic fibrosis has been the "gold standard", however, it is an invasive examination, there is a certain risk of complications, and because of the uneven distribution of hepatic fibrosis, there may be an inevitable result of sample error and observer error, it is also not easy to dynamic observation and following. With the development of magnetic resonance technology, magnetic resonance diffusion-weighted imaging by detecting the movement of water molecules within the organization reflects the physiological state and pathological conditions maybe can provide early diagnosis of the clinical evaluation of diseases. According to different degrees of hepatic fibrosis that results in the changes of ADC values of magnetic resonance diffusion-weighted imaging, to explore whether DWI can accurately stage the hepatic fibrosis and to further explore the mechanism of the reduction of ADC value with the increasing of hepatic fibrosis.ObjectiveTo investigate whether DWI imaging can accurately stage the extent of liver fibrosis and and to further explore the mechanism of the reduction of ADC value with the increasing of hepatic fibrosis.Materials and Methods30 rabbits were divided to two groups, five rabbits in control group, by intraperitoneal injection Sodium Chloride,25 test group rabbits by intraperitoneal injection of carbon tetrachloride oil mixture to establish hepatic fibrosis model. Scanned by MRI. To explore the mechanism of the changes of ADC value, after the ligation of hepatic left lateral hepatic artery and portal vein roots, each model were scanned again by the same sequence. Diffusion-weighted imaging using spin-echo-planar imaging sequences, diffusion-sensitive gradient b value were set as 300 s/mm2,500 s/mm2,700 s/mm2, 1000s/mm2.Images to be obtained through the ADW4.4 Workstation, the ADC values of each model were measured on hepatic left lateral lobe, right lobe of liver and left lateral lobe after ligation. After MRI, the rabbits'liver were taken the pathological examination, pathological liver tissue levels should correspond with the measuring levels of ADC values. Groups were divided according to pathological stages. Analysis with SPSS 13.0 statistical software.ResultsWith the progress of hepatic fibrosis. ADC values gradually decreased. ADC values of left lateral lobe after ligation significantly reduced, but not zero, and no changes with the corresponding of hepatic fibrosis. As the b value increases, image quality decreased, and the ADC value is gradually reduced. b value of 300 s/mm2,the difference between S2 and the other phases were statistically significant, but the difference between S0 and S1, S3 and S4 were not statistically significant, b value of 500 s/mm2,700 s/mm2,1000 s/mm2, S0 and S2, S3, S4 can be distinguished, regardless of the b values, SO and S1,S3 and S4 were not statistically significant different.ConclusionThe preliminary findings show that, DWI can not accurately distinguish different degrees of hepatic fibrosis, but can be a rough estimate of hepatic fibrosis. This study initially confirmed that the main reasons of vary degrees of hepatic fibrosis leading to a reduction in ADC values is the disorder of intrahepatic microcirculation and causes a decrease of blood flow, while the Brownian motion of water molecules is limited and can be neglected.