Noninvasive assessment of liver fibrosis staging with MR elastography versus ultrasound real-time shear wave elastography in a rabbit model / 中华放射学杂志

ABSTRACT

Objective:To explore the value of MR elastography (MRE) and shear wave elastography (SWE) for staging liver fibrosis in a rabbit model.Methods:From March to November 2020, 200 healthy New Zealand white rabbits were randomly divided into control group ( n=40) and liver fibrosis group ( n=160) by random number table method. The volume ratio of CCl 4 and olive oil was 1∶1 to prepare 50% CCl 4 oil solution, and the experimental rabbits in the liver fibrosis group were subcutaneously injected with 50% CCl 4 olive oil solution. It was injected once a week at the dose of 0.1 ml/kg in the first to third weeks, once a week at the dose of 0.2 ml/kg in the 4th to 6th weeks. The dose of 0.1 ml/kg was injected twice a week from week 7 to 16. The control group were subcutaneously injected with an equal dose of normal saline. At the end of the 4th, 8th, 12th, and 16th week, 40 and 10 animals in the liver fibrosis group and the control group were randomly selected by random number table method for MRE and SWE, respectively, to obtain the liver elastic stiffness (LS), which were recorded as LS MRE and LS SWE. After the examination, the experimental rabbits were sacrificed and liver tissue of rabbits were taken for histopathological Scheuer staging, and they were divided into F0-F4 groups. One-way ANOVA was used to evaluate the differences of LS MRE and LS SWE in different stages of liver fibrosis. Spearman correlation was used to analyze the correlation between LS and pathological stages. The receiver operating characteristic curve was used to evaluate the efficacy of LS MRE and LS SWE in diagnosing liver fibrosis staging, and the area under the curve (AUC) was compared using the Z test. Results:Totally 162 rabbits were included, which covered F0 ( n=38), F1 ( n=33), F2 ( n=35), F3 ( n=31) and F4 ( n=25). Significant differences of LS MRE and LS SWE values were found among different stages of liver fibrosis ( F=295.29, 102.40, both P<0.001). LS MRE, LS SWE were both positively correlated with liver fibrosis stage ( r=0.93, 0.81, both P<0.001). The AUC of LS MRE for diagnosing liver fibrosis stages ≥F1, ≥F2, ≥F3, and ≥F4 were 0.955, 0.967, 0.996, and 0.980, respectively; the AUC of LS SWE were 0.856, 0.880, 0.974, and 0.953, respectively. The AUC of liver fibrosis stage ≥ F1, ≥ F2 for LS MRE value were greater than LS SWE value ( Z=2.93, 3.29, P=0.003, 0.001), and the AUC of ≥F3, ≥F4 had no significant differences ( Z=1.58, 1.68, P=0.115, 0.093). Conclusion:Both MRE and SWE can accurately predict the stage of liver fibrosis in experimental rabbits, and MRE is better than SWE in diagnosing early liver fibrosis.