Diagnostic value of diffusion kurtosis imaging in assessing liver fibrosis / 中华放射学杂志

ABSTRACT

Objective To investigate the diagnostic value of diffusion kurtosis imaging(DKI)in the classification of hepatic fibrosis. Methods Thirty-five male SD rats were randomly divided into two groups:the hepatic fibrosis group(n=28)and the control group(n=7). The rats in hepatic fibrosis group were randomly divided into 4 subgroups and seven rats per group, the rats were administrated 50％ CCl4 intraperitoneally twice a week to establish hepatic fibrosis , and the four subgroups were injected 2, 4, 6, and 8 weeks, respectively. The rats in the control group were administrated same dose of olive oil for 8 weeks. One rat in hepatic fibrosis group was died of liver failure in the 7th week, and a total of 27 fibrosis experimental rats and 7 control rats were finally included in this study. DKI was performed at the end of the injection period for all rats, the apparent diffusion(D)and kurtosis(K)values were evaluated. Rats were sacrificed immediately after MRI scan and liver specimens were collected. The liver tissues were examined by pathology, liver fibrosis degree, which was graded from S0 to S4, and inflammatory activity, which was graded from G0 to G3 were graded. The difference of D value and K value between different liver fibrosis and inflammatory activity scores was compared by one-way ANOVA(normal distribution)or Kruskal-Wallis test(skewed distribution). Spearman correlation analysis and multiple regression analysis were used to reveal the correlation between DKI parameters and fibrosis staging/necroinflammatory activity grade. To confirm the efficiency of using the ROC curve of DKI parameters to qualify the liver fibrosis grade, which grade was≥3. Results Seven, 6, 6, 7, 8 rats were diagnosed as S0 to S4, respectively. The difference of D value and K value among different fibrosis grades was statistically significant(P<0.05). D value and the degree of fibrosis was negatively correlated(r=-0.650, P<0.01);K value and liver fibrosis grade no correlation(r=0.336, P=0.080). Thirteen, 6, 8, 7 rats were diagnosed as G0 to G3, respectively. D value was negatively correlated with inflammatory activity(r=-0.590, P=0.001);K value was no correlation with inflammatory activity(r=0.169, P=0.389). Compared with inflammatory activity, fibrosis classification was an independent factor in determining D values(P=0.001). ROC analyses demonstrated an area under the curve(AUC)of D value, K value, D value combined with K value in the diagnosis of liver fibrosis grading ≥ 3 level were 0.781, 0.672 and 0.833, respectlively. The sensitivity and specificity of D value combined with K value were 83.3％ and 75.0％, respectively. Conclusion DKI imaging is of great value in the classification of hepatic fibrosis and can be used as an effective method for the diagnosis of fibrosis.