钆塞酸二钠增强MRI评估肝功能:信号强度与T1弛豫时间相关参数的比较

Gd-EOB-DTPA-Enhanced MRI for Evaluation of Liver Function:Comparison between Signal Intensity and T1 Relaxation Time-Based Indices

目的比较Gd-EOB-DTPA增强肝实质的信号强度(SI)与T1弛豫时间相关参数对肝功能的评估能力。方法前瞻性搜集慢性乙型肝炎肝硬化肝功能为Child-Pugh A级(LCA)者48例,Child-Pugh B级(LCB) 40例,Child-Pugh C级(LCC) 13例。搜集同期无肝病病史肝功能正常的健康体检者(NLF) 21例作为对照组。采用GdEOB-DTPA行常规肝脏扫描(平扫、动脉期、门静脉期、移行期及肝胆期)。采用Look-Locker序列分别于增强前及肝胆期于近肝门层面行T1mapping扫描。测量增强前及肝胆期肝脏SI (SIpre/SIHBP)、肝脏T1弛豫时间(T1pre/T1HBP),竖脊肌SI (竖脊肌pre/竖脊肌HBP),计算增强后肝脏相对强化率(RE)、肝脏-肌肉增加率(r LMR)、肝脏T1弛豫时间减低率(rr T1)及肝脏T1弛豫率增加值(ΔR1)。采用单因素方差分析比较不同肝功能级别SI与T1弛豫时间相关参数。采用ROC曲线评价不同参数鉴别NLF-CH-LCA与LCB-LCC的效能。结果 NLF与LCB或LCC组SIpre差异有统计学意义(P <0. 05);LCC与NLF或LCA、LCA与LCB组RE差异有统计学意义(P <0. 05);NLF、LCA分别与LCB或LCC组比较SIHBP、r LMR差异均有统计学意义(P <0. 05);NLF与其他各组、LCA与LCC组比较T1pre差异均有统计学意义(P <0. 05);除NLF与LCA组外,余两两比较T1HBP、rr T1、ΔR1差异均有统计学意义(P <0. 05)。SIpre、SIHBP、RE与r LMR诊断Child-Pugh分级≥B级ROC曲线下面积分别为0. 661、0. 790、0. 698、0. 901,T1pre、T1HBP、rr T1与ΔR1诊断Child-Pugh分级≥B级ROC曲线下面积分别为0. 719、0. 948、0. 921、0. 946。结论 Gd-EOB-DTPA增强SI与T1弛豫时间相关参数可定量评估肝功能。增强后的参数优于增强前,矫正后SI相关参数优于矫正前,T1弛豫时间相关参数总体优于SI相关参数。

Objective To compare the diagnostic performance of Gd-EOB-DTPA-enhanced signal intensity(SI)and T1 relaxation time-based indices for evaluation of liver function.Methods 101 patients with chronic viral hepatitis B and cirrhosis were separated into three groups in this prospective study:liver cirrhosis with Child-Pugh A(LCA,n=48),ChildPugh B(LCB,n=40),Child-Pugh C(LCC,n=13).21 healthy volunteers with normal liver function(NLF)were enrolled as a control group.All subjects underwent Gd-EOB-DTPA-enhanced MR imaging native phase,arterial phase,portal venous phase,transitional phase and hepatobiliary phase(HBP).Look-Locker sequences with the same geometry position(a the level of porta hepatis)were performed before Gd-EOB-DTPA administration and in HBP to acquire T1 mapping.The SI values of the liver(SIpre/SIHBP),paravertebral muscle(muscle pre/muscle HBP)and T1 relaxation time of the liver(T1 pre/T1 HBP)before Gd-EOB-DTPA administration and in HBP were measured.The relative enhancement of the liver(RE),increase rate of the liver-to-muscle ratio(r LMR),reduction rate of T1 relaxation time of the liver(rrT1)andΔR1 were calculated.One-way ANOVA was performed to compare SI and T1 relaxation time-based indices among different liver function groups.ROC curve analysis was used to evaluate the diagnostic performance of SI and T1 relaxation time-based indices in discriminating NLF-CH-LCA and LCB-LCC.Results SIpre showed significantly different(P<0.05)between NLF and LCB or NLF and LCC.RE showed significantly difference(P<0.05)between LCC and NLF or LCA,between LCA and LCB.SIHBP and r LMR were significantly(P<0.05)higher in NLF and LCA compared to LCB or LCC.T1 pre was significantly(P<0.05)higher in NLF compared to other groups,significantly different(P<0.05)was also found between LCA and LCC.T1 HBP,rrT1 andΔR1 showed significantly different(P<0.05)between any two groups except between NLF and LCA.The areas under ROC curve of SIpre,SIHBP,RE and r LMR for discriminating NLF-CH-LCA and LCB-LCC were 0.661,0.790,0.698 and 0.901 respectively,the areas under ROC curve of T1 pre,T1 HBP,rrT1 andΔR1 for distinguishing NLF-CH-LCA and LCB-LCC were 0.719,0.948,0.921 and 0.946 respectively.Conclusion Gd-EOB-DTPA-enhanced SI and T1 relaxation time-based indices are feasible for assessing liver function.The indices post-enhancement are better than pre-enhancement,the indices after rectification have an advantage over before,indices derived from T1 relaxation time are superior to SI-based indices.