T2值定量评估不同肝纤维化分期大鼠肝脏铁沉积

目的分析T2值定量评估不同肝纤维化分期大鼠肝脏铁沉积的价值。方法以60只SD雄性大鼠建立大鼠肝纤维化模型。造模第5~12周期间每周对1~6只大鼠采集上腹部T2 mapping,测量肝脏T2值;之后以病理检查评估肝脏纤维化分期、脂肪及铁质病理分级。比较不同铁质病理分级大鼠肝脏T2值的差异,分析肝铁质病理分级与T2值及纤维化S分期的相关性。绘制T2值诊断肝铁质病理分级的受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评价脂肪、铁质病理分级及肝纤维化分期对T2值的影响。结果共纳入40只大鼠,包括肝脏纤维化S0期、S1期各6只,S2期8只,S3期、S4期各10只;其中铁质病理分级0级7只,1级9只,2级12只,3级10只,4级2只;脂肪病理分级0级5只,1级8只,2级12只,3级15只。肝纤维化分期与铁质病理分级呈正相关(tau-b=0.851,P<0.001),铁质病理分级与T2值呈负相关(rs=-0.803,P<0.001)。不同铁质病理分级大鼠肝脏T2值总体差异有统计学意义(H=26.367,P<0.001);除铁质病理0级与1级、1级与2级间肝脏T2值差异无统计学意义(P均>0.05)外,其余各铁质病理分级间T2值差异均有统计学意义(P均<0.05)。T2值诊断铁质病理分级0级vs.1~3级、0~1级vs.2~3级、0~2级vs.3级的AUC分别为0.965、0.871及0.939。铁质、脂肪病理分级及纤维化分期的交互作用对肝脏T2值无明显影响(F=1.43,P>0.05)。结论T2值对定量评估肝纤维化大鼠肝脏铁沉积具有一定价值。

T2 value for quantitative evaluation of liver iron deposition in rats with different stages of hepatic fibrosis

Objective To analyze the value of T2 value for quantitative evaluation of liver iron deposition in rats with different stages of hepatic fibrosis. Methods Sixty male SD rats were used to establish liver fibrosis models. At the 5th to 12th week of modeling, 1-6 rats were selected for upper abdominal T2 mapping every week, and T2 values of liver were measured. Then histopathological examination was performed to assess the grade of liver fibrosis and the pathological grade of fat and iron. Liver T2 values were compared among rats with different pathological grades of iron. The correlations of pathological grades of hepatic iron, T2 values and S stages of liver fibrosis were analyzed, respectively. Receiver operating characteristic (ROC) curve of T2 value for assessing pathological grades of hepatic iron was drawn, the area under the curve (AUC) was calculated. The impacts of pathological grades of fat, iron and hepatic fibrosis on T2 value were analyzed. Results Forty rats were enrolled in this study, including 6 rats with hepatic fibrosis stage S0, 6 with stage S1, 8 with stage S2, 10 with stage S3 and 10 rats with stage S4; 7 rats with iron pathological grade 0, 9 with grade 1, 12 with grade 2, 10 with grade 3 and 2 rats with grade 4; 5 rats with fat pathological grade 0, 8 with grade 1, 12 with grade 2 and 15 with grade 3. The liver fibrosis stages were positively correlated with iron pathological grades (tau-b=0.851, P<0.001). And a negative correlation was observed between iron pathological grade and T2 value (r_s=-0.803, P<0.001). There were statistical differences of liver T2 values among rats with different iron pathological grades (H=26.367, P<0.001), and pairwise comparisons showed significant differences of liver T2 values in all iron pathological grades (all P<0.05) except for grade 0 and 1 as well as grade 1 and 2 (both P>0.05). The AUC of T2 value for assessing iron pathological grade 0 vs. 1-3, grade 0-1 vs. 2-3, grade 0-1 vs. 2-3 was 0.965, 0.871 and 0.939, respectively. The interaction of pathological grades of iron and fat and fibrosis stages had no obvious impact on liver T2 value (F=1.43, P>0.05). Conclusion T2 value had certain value for quantitative evaluation of liver iron deposition in rats with liver fibrosis.