Study On The Diagnosis Of Focal Liver Lesions By 3.0 T Magnetic Resonance Routine Sequences And IVIM Imaging

Objective:1.To explore the diagnostic value of 3.0 T magnetic resonance imaging（T₁WI,T₂WI,and DWI）and 3D-LAVA dynamic contrast enhancement in the qualitative diagnosis of focal liver lesions.2.To evaluate quantitatively the parameters of DWI and IVIM imaging in benign and malignant focal liver lesions.3.To analyze the correlation between relative enhancement ratio of focal liver lesions and the parameters of DWI and IVIM imaging.Methods:The imaging data of 75 patients with focal hepatic lesions（a total of 96 lesions）in Hebei General Hospital from January 2017 to December2020 were retrospectively analyzed（including malignant lesions:24hepatocellular carcinomas,22 intrahepatic metastases,and 2 intrahepatic cholangiocarcinomas,and benign lesions:27 hepatic hemangiomas,18 liver cysts,and 3 hepatic abscesses）.All patients underwent conventional plain scan examination of 3.0 T magnetic resonance imaging,IVIM-DWI（b values of 0,30,50,80,100,200,400,600,800,1000,1200 s/mm²）examination,and3D-LAVA dynamic contrast enhancement examination.Qualitative analysis of the image signal level of the lesion was performed,and the relative enhancement ratio of the lesion was calculated according to the signal intensity on the different phases（mask,arterial,and portal phase）.The ADC,D_slow,D_fast,and f values of the lesions were measured through the post-processing operation.Data analysis:（1）The nonparametric Mann-Whitney U test was used to analyze the differences between benign and malignant lesions,hepatocellular carcinomas and liver hemangiomas,hepatocellular carcinomas and liver metastases.（2）The receiver operating characteristic curve was used to evaluate the diagnostic value of the parameters,and the cut-off value was calculated according to the Youden index.（3）The Spearman correlation test was used to analyze the correlation between the relative enhancement ratio of the lesions in the artery and portal phases and the parameters of DWI and IVIM imaging.Results with a P value less than 0.05were considered statistically significant.Results:1.There was an amount of signal overlap among various lesions in the conventional sequences examination,while most lesions showed typical image features in the 3D-LAVA dynamic contrast enhancement examination.2.The group of benign liver lesions have the higher D_slow and ADC values than malignant liver lesions,and D_slowvalue has the highest diagnostic value(ACU=0.964,cutoff value=1.24×10^-3 mm²/s),while D_fastand f values had no statistical significance（P>0.05）.When the lesions were analyzed separately,the ADC value in the diagnosis of hemangiomas and hepatocellular carcinomas was higher than other parameters(AUC=0.954,cutoff value=1.39×10^-3mm²/s).There was no significant difference in the parameters between hepatocellular carcinomas and liver metastases（P>0.05）.3.There was a lower degree of correlation between the ADC value and the relative enhancement ratio in the portal phase of the focal liver lesions（r=0.312,P<0.05）.Conclusions:1.Combined 3.0 T magnetic resonance routine plain scan sequences and 3D-LAVA dynamic contrast enhancement examination can distinguish most of the focal liver lesions（FLLs）.2.DWI and IVIM-DWI examination can distinguish benign and malignant liver lesions,and the D_slow value has the highest diagnostic value,with a cutoff value of 1.24×10^-3mm²/s.3.DWI and IVIM-DWI technology can differentiate hepatocellular carcinomas and hemangiomas,and the ADC value has the highest diagnostic value,and the cutoff value is 1.39×10^-3 mm²/s.4.IVIM-DWI and DWI techniques are not suitable for the differential diagnosis of hepatocellular carcinomas and liver metastases.5.The enhancement degree of focal liver lesions in the portal phase is correlated with the ADC value.