| Objective:To investigate the diagnostic value of whole-liver ADC histogram parameters and magnetic resonance T2WI liver signal intensity index(SII)in liver fibrosis stage of rats.Methods:44 healthy and clean SD rats were obtained from the experimental animal center of Lanzhou University,37 rats were randomly selected as experimental groups,the remaining 7 rats were used as healthy controls.Using Classical culture method,Liver fibrosis in rats was induced by intraperitoneal injection of 0.3 mL/100g40%CCl4 olive oil twice a week for 12 weeks.After one week of normal feeding in all rats,two rats per week in the control group and four rats in the experimental group at the beginning of the second week after modeling,both were scanned by 3.0T MRI.The sequences included Axial T1-weighted imaging(TIWI),Axial T2-weighted imaging(T2WI),Axial DWI(b=0s/mm~2,800s/mm~2).The original MRI image obtained by scanning is stored in DICOM format.Histogram analysis of whole liver ADC using FireVoxel software and parameters including ADC minimum,maximum,mean,median,mode,standard deviation(SD),Inhomogeneity,skewness,kurtosis,entropy,10th,25th,50th,75th,90th percentiles were calculated.The SII was calculated as the signal intensity ratio between the hepatic parenchyma and the right erector spinae muscles on the same section of FS T2WI MR images for all included cases.analyzeing the correlation,and staging value between the parameters of histograms and the indexes of liver signal intensity on T2WI and the stages of liver fibrosis.Receiver operating characteristics(ROC)analyses were further established to evaluate the potential diagnostic performance for differentiating liver fibrosis stages.Result:1.Animal model pathological results:A total of 38 rats were included,and7,7,9,and 8 rats were diagnosed as F1–F4,7 healthy rats of control group were classified into F0.2.Results showed the inhomogeneity,skewness,Kurtosis,entropy,and 75th percentiles exhibited significant differences among the pathological fibrosis stages(P<0.05).Kurtosis was found to be the most meaningful parameter in differentiating fibrosis stages,AUC were 0.732(95%CI:0.568-0.897),0.773(95%CI:0.606-0.940),0.789(95%CI:0.717-0.993)respectively,followed by entropy.3.There was significant difference of SII value in the stages of liver fibrosis in F0and F1-4,F0-1 and F2-4,F0-2 and F3-4 groups.4.Spearman analysis showed that rs=0.511,P=0.040 between kurtosis and fibrosis degree;rs=-0.406,P=0.012 between SII value and fibrosis degree.5.The diagnosis accuracy for different stages of liver fibrosis:Statistical analysis,the kurtosis of ROC curve showed that stage 1 or greater(?F1),stage 2 or greater(?F2),stage 4 or greater(?F4),the area under curve was 0.732(sensitivity:66.7%?specificity:76.4%),0.773(sensitivity:78.6%?specificity:76.4%),0.789(sensitivity:88.9%?specificity:87.5%),respectively.The next is entropy(AUC=0.737,0.667,0.747).The 75th percentile for the diagnosis of stage 3 or greater(?F3)liver fibrosis area under the ROC curve is 0.841,sensitivity were 100%,and the specificity were 94.1%.The area under the curve of SII were 0.906(sensitivity 85.7%?specificity90.3%),0.863(sensitivity99.4%?specificity75.6%),0.755(sensitivity 85.7%?specificity70.7%?)respectively.Conclusion:1.The kurtosis and entropy of ADC histogram parameters are helpful for the diagnosis and staging of liver fibrosis,in which the kurtosis is better than the entropy;the inhomogeneity,skewness and 75 percentile have good diagnostic value for liver fibrosis with staging?F3,and the 75th percentile is the best.2.SII value can diagnosis normal liver from fibrotic liver,and SII value has a certain value in the diagnosis of liver fibrosis in?F2 and?F3 groups.3.kurtosis was positively correlated with liver fibrosis level,and SII value was negatively correlated with liver fibrosis level. |
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