The Value Of Mr T1ρ Imaging In Staging Liver Fibrosis In Patients With Chronic Hepatitis B

Objective To explore the value of MR T1ρ imaging in staging liver fibrosis in patients with chronic hepatitis B.Materials and methods Fifteen healthy control subjects(N)and thirty-senven chronic hepatitis B patients with histopathologic results(S1/S2/S3-S4=15/13/9)were recruited and underwent MR T1ρ scanning.The T1ρ map was generated by postprocessing the raw data.T1ρ value was measured by two doctors independently with double-blank.The intraclass correlation coefficient(ICC)was used to assess interobserver agreements on T1ρ measurement.One-way analysis of variance(one-way ANOVA)and least significant difference(LSD)was used to compare the T1ρ value,age and body mass index(BMI)of normal control subjects and patients in different pathological stages of liver fibrosis.Receiver operating characteristic(ROC)curves and the area under the ROC curve(AUC)were used to evaluate the efficacy of T1ρ value for diagnosing the stage of hepatitis B liver fibrosis.And optimal diagnostic threshold of T1ρ value was determined according to Yodden index(Yodden index = sensitivity+specificity-1),and sensitivity and specificity were calculated.Pearson correlation test(normal distribution)or Spearman rank correlation test(non-normal distribution)was used to analyze the correlation between T1ρ values and age,BMI and related blood parameters.Results The interobserver agreements of two doctors on T1ρ measurement of left hepatic lobe and right hepatic lobe of all enrollees was good(both ICC value>0.93).With the progressing of liver fibrosis,T1ρ value increased.T1ρ value were(45.00±1.31)ms,(48.08±1.54)ms,(50.01±1.52)ms and(52.63±1.16)ms in N group,S1 group,S2 group and S3-4 group,respectively,and statistically significant differences were observed among all groups(F=61.372,P < 0.001).Further pairwise comparison showed N vs.S1,N vs.S2,N vs.S3-4,S1 vs.S2,S1 vs.S3-4 and S2 vs.S3-4 were significantly different(all P value<0.001).ROC analysis showed the AUC of≥S1were 0.971,the threshold of T1ρ value were 46.00 ms,and sensitivity and specificity were 97.3% and 93.3%;the AUC of ≥S2 were 0.941,the threshold of T1ρvalue were 48.86 ms,and sensitivity and specificity were 90.9% and 83.3%;the AUCof ≥S3 were 0.974,the threshold of T1ρ value were 50.22 ms,and sensitivity and specificity were 100% and 86.0%.T1ρ value was highly positively correlated with liver fibrosis staging(r=0.884,P<0.001),not correlated with age(r=-0.240,P=0.087)and BMI(r=0.077,P=0.588),moderately positively correlated with collagen type IV(CIV)(r=0.384,P=0.036),and moderately negatively correlated with ratio of albumin to globulin(A/G)(r=-0.368,P=0.029).Conclusions MR T1ρ imaging can be used to detect and stage liver fibrosis in patients with chronic hepatitis B.T1ρ values are strongly correlated with liver fibrosis stage,not affected by age and BMI,and slightly affected by CIV and A/G.