Evaluation Of Hepatic Functional Reserve By Hepatocyte Enhancement Fraction Compared With Indocyanine Green Retention At 15 Minutes

Objective Indocyanine Green Retention at 15 minutes was used as the reference standard to investigate the feasibility of a combination of gadolinium?ethoxybenzyl diethylenetriamine pentaacetic acid,（Gd-EOB-DTPA）enhanced T1 mapping and hepatocyte enhancement fraction（HEF）in quantitative assessment of hepatic functional reserve.Methods Between December 2019 to December 2020,we retrospectively include 104patients who were admitted to the First People’s Hospital of Yunnan Province and completed Gd-EOB-DTPA enhanced MRI with indocyanine green（ICG）retention experiment within one week.Patients were divided into two groups according to the indocyanine green retention at 15 minutes（ICG R15）.There were 86 patients with ICG R15<30%and 18 patients with ICG R15≥30%.Transection T1 mapping images near the porta hepatis were collected before and 10 and 20 minutes after enhancement,respectively.Four ROIs were selected to measure the T1 relaxation time at each time point,and decrease rate of T1 relaxation time（ΔT1）,increase of T1 relaxation rate（ΔR1）,HEF,and its uptake coefficient（K）were calculated.Independent samples t test was performed to compare T1 relaxation time,ΔT1,ΔR1,K and HEF between ICG R15≤30 group and ICG R15>30 group.Receiver operating characteristic curves（ROCs）were done to compare the diagnostic performance of T1 relaxation time,ΔT1,ΔR1,K and HEF in different time point.Results The T1 relaxation time values increased（t=-4.751、-6.568、-7.402）,while theΔT1,ΔR1 K and HEF values decreased（t=7.901、8.846、7.905、8.991、9.074、10.931、8.193、10.063）,with the development hepatic functional reserve damage.Differences in T1 relaxation time,ΔT1,ΔR1,K and HEF were found between different groups（all P<0.01）.T1 relaxation time,ΔT1,ΔR1,K,and HEF area under the ROC curve at 20 minutes after enhancement（0.935、0.926、0.93、0.944、0.944,all P<0.01）are higher than at 10 minutes after enhancement（0.911、0.896、0.91、0.912、0.912,all P<0.01）.Diagnostic value of HEF and K at 20 minutes after enhancement is the best among those.There is statistically significant difference of the area under the curve among the T1relaxation time before the enhancement and each parameter at 10 minutes and 20 minutes after the enhancement（all P<0.05）.There is no statistically significant difference in the area under the curve of each parameter at 10 minutes and 20 minutes after enhancement（all P>0.05）.Conclusions Gd-EOB-DTPA enhanced T1 Mapping imaging is an effective method to quantitative evaluate hepatic functional reserve.The diagnostic efficiency of all parameter at 20 minutes after enhancement is better than 10 minutes.Among them,HEF_20min and K_20min have the highest diagnostic efficiency for hepatic functional reserve.