钆塞酸二钠增强T1 mapping成像肝功能评估肝胆期扫描时间的优化

Optimization of hepatobiliary phase scan time for the assessment of liver function using T1 mapping on Gd-EOB-DTPA-enhanced magnetic resonance imaging

目的:探讨钆塞酸二钠Gd-EOB-DTPA增强T 1 mapping成像评估肝功能时合理的肝胆期扫描时间。方法:纳入124例乙肝肝硬化患者[肝功能Child-Pugh A级(LCA)63例、B级(LCB)47例、C级(LCC)14例]及23例健康体检者(NLF)。患者均采用Gd-EOB-DTPA行上腹部平扫及增强扫描,并采用Look-Locker序列分别于平扫、增强后10 min、15 min及20 min采集T 1 mapping图像。测量肝脏T 1弛豫时间,并计算增强后10 min、15 min及20 min肝脏T 1弛豫时间减低率(ΔT 1)及弛豫率增加值(ΔR 1)。采用重复测量方差分析比较不同级别肝功能组不同时间T 1、ΔT 1及ΔR 1,采用ROC曲线评价T 1、ΔT 1及ΔR 1鉴别NLF-LCA与LCB-LCC组的效能。结果:NLF、LCA、LCB组增强后10 min、15 min及20 min T 1弛豫时间逐渐减低,ΔT 1及ΔR 1逐渐增加,LCC组增强后10 min、15 min及20 min T 1弛豫时间逐渐增加,ΔT 1逐渐减低。不同时间点T 1弛豫时间、ΔT 1及ΔR 1差异均有统计学意义(F=23.125,28.061,67.421,P=0.000)。不同组别T 1弛豫时间、ΔT 1及ΔR 1差异均有统计学意义(F=82.686、49.041、70.963,P=0.000)。增强后10 min、15 min与20 min的T 1弛豫时间鉴别NLF-LCA与LCB-LCC组的ROC下面积分别为0.959、0.949、0.952。ΔT 1鉴别两者的ROC下面积分别为0.880、0.879、0.894。ΔR 1鉴别两者的ROC下面积分别为0.942、0.934、0.939。增强后10 min、15 min与20 min的T 1弛豫时间、ΔT 1及ΔR 1 ROC下面积差异均无统计学意义。结论:采用钆塞酸二钠增强T 1 mapping成像评估肝功能时,于增强后10 min采集肝胆期图像可满足诊断需求。

Objective:To investigate the hepatobiliary phase(HBP)scan time for the assessment of liver function using T 1 mapping on Gd-EOB-DTPA-enhanced magnetic resonance imaging(MRI).Methods:Totally,124 patients with chronic viral hepatitis B and cirrhosis were classified into three groups as follows:liver cirrhosis with Child-Pugh A(LCA,n=63),Child-Pugh B(LCB,n=47),and Child-Pugh C(LCC,n=14).Twenty-three healthy volunteers with normal liver function(NLF)were enrolled as control group.All patients underwent Gd-EOB-DTPA-enhanced MRI.To obtain T 1 mapping,Look-Locker sequences before and at 10,15,and 20 minutes after Gd-EOB-DTPA administration were acquired.T 1 relaxation time of liver was measured on T 1 mapping,reduction rate of T 1 relaxation time(ΔT 1),and increase of relaxation rate(ΔR 1)between pre-and post-enhancement were calculated.Repeated-measures analysis of variance was performed to compare T 1 relaxation time,ΔT 1,andΔR 1 among different liver function groups and different time points.Receiver operating characteristic(ROC)curve was drawn to determine the predictive effect of these parameters in discriminating NLF-LCA and LCB-LCC.Results:T 1 relaxation time of NLF,LCA,and LCB groups progressively increased from 10 min,15 min to 20 min post-contrast,ΔT 1 andΔR 1 showed a constant decrease from 10 min to 20 min.T 1 relaxation time of LCC gradually decreased andΔT 1 increased from 10 min to 20 min.T 1 relaxation time,ΔT 1 andΔR 1 showed significant difference among different time points(F=23.125,28.061,67.421,P=0.000)and different groups(F=82.686,49.041,70.963,P=0.000).The areas under the ROC curve of T 110 min,T 115 min,and T 120 min for discriminating NLF-LCA and LCB-LCC were 0.959,0.949,and 0.952,respectively.The areas under the ROC curve ofΔT 110 min,ΔT 115 min,andΔT 120 min were 0.880,0.879,and 0.894,respectively.The areas under ROC curve ofΔR 110 min,ΔR 115 min,andΔR 120 min were 0.942,0.934,and 0.939,respectively.No significantly difference(P>0.05)was found among the three time points.Conclusions:The 10 min HBP is feasible for assessing liver function using T 1 mapping on Gd-EOB-DTPA-enhanced MRI.