Gd-EOB-DTPA Enhanced MRI T₁ Mapping Combined With Standard Liver Volume Ratio For Estimation Of Liver Function

Objective:To explore the application value of Gd-EOB-DTPA enhanced MRI T₁ mapping combined with standard liver volume ratio（LV/SLV）for estimation of liver function.Methods:80 patients underwent Gd-EOB-DTPA enhanced MRI T₁ mapping were prospectively enrolled.Variable flip angles T₁ mapping sequences were performed before and after 20 minutes（hepatobiliary phase,HBP）with Gd-EOB-DTPA injection.Clinic data of patients were collected and were used to classify different groups.Patients were divided into three groups according to Child-Pugh score as follows:NLF（normal liver function）（n=26）,LCA（Liver cirrhosis with Child-Pugh A）（n=30）,LCB+LCC（Liver cirrhosis with Child-Pugh B+C）（n=24）,and divided into two groups according to MELD:good liver function（MELD≤8）（n=57）and poor liver function（MELD≥9）（n=23）.All the MRI data were transferred to the Siemens Syngo workstation.The T₁ relaxation times were measured by using operator-defined regions of interest（ROIs）.Five ROIs with 0.35cm² area was drawn on portal hepatic level of the T₁ maps.The average T₁ value on pre-contrast and HBP were respectively recorded as T_{1 pre},T_{1 post},and then reduction rate of T₁ relaxation time[△T₁,△T₁=(T_1pre-T_1post)/T_1pre×100%]was calculated.The liver volumes（LV）were measured on HBP imagings.The body surface areas（BSA）were calculated with the heights and weights of patients according to the following formula:BSA（m²）=weight（kg）^0.425×height（cm）^0.725×0.007184,and standard liver volumes（SLV）were calculated as follows:SLV（ml）=706.2×BSA（m²）+2.4.The liver volume to standard liver volume ratio（LV/SLV）was calculated.The one-way ANOVA was used to compared the indexes(T_1post,T_1post×LV/SLV,ΔT₁,ΔT₁×LV/SLV)in different liver function groups of NLF,LCA,LCB+LCC.The t-test was used to compared the indexes(T_1post,T_1post×LV/SLV,ΔT₁,ΔT₁×LV/SLV)in MELD≤8 and MELD≥9 groups.Spearman correlation analysis was applied to analyze the correlation of all indexes with Child-Pugh and MELD system.Receiver operator characteristic curves（ROC）were drawn and compared the area under the curve of all indexes to compare the diagnostic performance of T_1post,T_1post×LV/SLV,ΔT₁,ΔT₁×LV/SLV.Results:All groups showed the significant difference among T_1post,T_1post×LV/SLV,ΔT₁,ΔT₁×LV/SLV（P<0.05）.The AUCs ofΔT₁×LV/SLV in the MELD≤8 and MELD≥9（0.902）,NLF and LCA（0.771）,NLF and LCB+LCC（1.000）,LCA and LCB+LCC（0.924）were slightly higher than that ofΔT₁（0.886,0.764,0.992,0.904,respectively）.The T_1post（AUC 0.824）and T_1post×LV/SLV（AUC 0.789）showed a significant better than others indexes between the MELD groups.For the Child-Pugh groups,the AUCs of T_1post and T_1post×LV/SLV were0.713 and 0.687（between NLF and LCA）,0.987 and 0.973（between NLF and LCB+LCC）,0.915 and 0.871（between LCA and LCB+LCC）,respectively.The T_1post×LV/SLV showed a slightly lower AUCs among the different liver function groups than T_1post.Conclusion:1.The results of T_1post andΔT₁ based on Gd-EOB-DTPA enhanced MRI to estimate liver function were consistent with Child-Pugh and MELD scores.T_1post andΔT₁showed a useful value to assess liver function.2.ΔT₁×LV/SLV was more accurate for estimation of liver function.