The Value Of IVIM-DWI In The Differential Diagnosis Of Benign And Malignant Focal Liver Lesions

1.PurposeThe purpose of this study is to assess the value of the intravoxel incoherent motion diffusion-weighted imaging(IVIM-DWI)parameters based on a bi-exponential model in differential diagnosis of benign and malignant focal liver lesions(FLLs).2.Materials and methodsForty-nine with 51 focal liver lesions,including 10 hepatic cysts,12 hemangiomas,13 hepatocellular carcinomas,3 cholangiocarcinomas and 12 metastasis,diagnosed in our hospital by needle biopsies,surgical pathology findings,clinical or follow-up tests during the period of January 2016 to January 2017,were retrospectively reviewed in this study.All the patients underwent conventional MRI combined with IVIM-DWI and dynamic contrast-enhancement MRI(DCE-MRI).IVIM-DWI images were acquired with 10 b values(b=0,25,50,80,150,200,400,600,800,1000 s/mm)to measure the apparent diffusion coefficient(ADC)based on a mono-exponential model and the slow apparent diffusion coefficient(slow ADC)and the fast apparent diffusion coefficient(fast ADC)and perfusion fraction(f)based on a multi-exponential model.The diffusion parameters were compared between benign and malignant groups and between lesions types in benign group by independent-samples T test,and between lesions types in malignant group by one-way ANOVA,their diagnostic value and testing threshold in identifying lesion malignancy was assessed by receiver operating characteristic curve(ROC).3.Results(1)The individual differences of ADC,slow ADC and f value in the benign group are statistically significant(P<0.05 for each),while that of the fast ADC value does not have statistical significance(P>0.05).(2)The individual differences of ADC,slow ADC,fast ADC and f value in the malignant group are not statistically significant(P>0.05 for each).(3)The differences of ADC and slow ADC value between the malignant and benign group are statistically significant(P<0.05 for each),while that of the fast ADC and f value does not have statistical significance(P>0.05 for each).The area of the ADC and slow ADC value under the receiver operating characteristic(ROC)curve are 0.995 and 0.996.When applying 1.245×10-3mm2/s as the testing threshold of the slow ADC,its diagnostic sensitivity and specificity are 100% and 92.9%.4.ConclusionDWI based on either mono-exponential or bi-exponential model are conductive to the differential diagnosis of common malignant and benign focal liver lesion(FLL).And the slow ADC value from a bi-exponential model based IVIM-DWI has even better diagnostic performance,while fast ADC and f value have little value in the diagnosis of malignant and benign focal liver lesion.