MR T_2 WI肝脏信号强度指标评估慢性乙型肝炎的价值

The Evaluation of Chronic Hepatitis B by the Signal Intensity Index of Live on MR Fat Suppressed T_2-weighted Imaging

目的探讨MR脂肪抑制T2WI肝脏信号强度指标(SII)评估慢性乙型肝炎炎症活动度(G)和纤维化程度(S)的价值。资料与方法慢性乙型肝炎患者32例,正常18例。扫描序列主要为脂肪抑制T2WI,肝脏SII为肝脏与右侧背肌信号强度之比。结果肝脏SII平均0.966±0.172。多因素方差分析G分组F=8.608,P=0.000;S分组F=4.032,P=0.009;G和S交互作用F=2.374,P=0.050。偏相关示SII与G间r=0.622,P=0.000;与S间r=-0.361,P=0.011。接受者工作特性(ROC)曲线示SII诊断中重度肝炎曲线下面积=0.925,P=0.000,最佳诊断界点SII=0.97。结论 MR脂肪抑制T2WI肝脏SII与慢性乙型肝炎炎症活动度呈显著正相关,其判断中重度炎症活动的值为>0.97。

Objective To assess the value of signal intensity index（SII） of liver on magnetic resonance（MR） fat suppressed T2-weighted imaging（T2WI） in evaluating the histological changes of chronic hepatitis B.Materials and Methods Thirty-two patients who were clinically and histologically diagnosed with chronic hepatitis B and 18 healthy subjects without history of liver disease received abdominal MRI.The major MRI sequence included a breath-trigger fat-suppressed fast recovery fast spin echo T2WI.The SII of liver was calculated as the signal intensity ratio between the hepatic parenchyma and right sacrospinalis muscles in the same MR section for fat-suppressed T2WI.Results The average SII of liver was 0.966±0.172.The multiple factor variance analysis showed significant difference for the SII of liver in grading of liver（G,F=8.608,P=0.000;S,F=4.032,P=0.009;interaction,F=2.374,P=0.050）.Partial correlation showed significant correlation between SII of liver and grading（r=0.622,P=0.000）,and between SII of liver and staging（r=-0.361,P=0.011）.Receiver operating characteristic（ROC） curve for the hepatic SII in predicting moderate-severe inflammatory activity showed area under the ROC curve was 0.925（P=0.000）,and cutoff point was 0.97.Conclusion There is significant positive correlation between the hepatic SII for MR fat-suppressed T2WI and the histological grading in patients with chronic hepatitis B.The hepatic SII for predicting moderate-severe inflammatory activity is more than 0.97.