The Application Value Of Multi-exponential Model DWI Is Assessed In Hepatocellular Carcinoma

Part IObjectiveAs the DWI application can be applied in the abdomen,especially for the increasing maturity of the application of liver lesions.But the application of DWIs is based on the traditional mono-exponential model.And some scholars put forward some deficiencies.Firstly,the traditional mono-exponential model ignores the microcirculation perfusion of living tissue which effects on ADC values.Secondly,the traditional mono-exponential model of DWIs which use two b values can calculate the ADC values,which exists relative instability.As a result,some researchers present bi-exponential model DWI with multiple b values can reflect and distinguish between the molecular diffusion movement and microcirculation perfusion in the organization.And it can be quantified diffusion(Dslow)and perfusion(Dfast,FF),respectively.At present,the comparison of mono-exponential and bi-exponential model was less in the application of HCC.Therefore,the purpose of this study is to investigate the DWI technique of mono-exponential and bi-exponential model which can be put into use in the diagnosis of hepatocellular carcinoma.Method This study screened the 30 cases of patients with hepatocellular carcinoma,the male 26 cases,female 4 cases,age 29~69(mean age,53.4±8.4 years).At the same time,20 cases of healthy subjects can be selected as control group,the male 5 cases,female 15 cases,age 21~51(mean age,32.6±1.1 years).All HCC patients and healthy volunteers were adopted by GE750 3.0 T magnetic resonance(MR),with 8 channel body standard array coil.Conventional MRI(axial SE T1W and T2WI,coronal SE T2WI)and DWI scanning(b-value:0,50,100,200,500,800,1000,2000,3000s/mm~2).B values of DWI images can be introduced to the ADW4.6 workstation.Using the MADC Functool software post-processing DWI image could get the parameters of mono-exponential and bi-exponential model for the color maps.Two experienced radiologists would apply ROI on the substantial part of tumor of b-value DWI imaging by manual,respectively.In order to avoid the pathological changes of hemorrhage and necrosis.Twice was measured,respectively.And then they were averaged.Simultaneously,it is ROIs on b value DWI imaging of on normal liver right lobe,left medial segment,respectively.Measured twice,and then averaged.Avoiding peripheral vascular artifacts and surrounding lesions.Then,all data was used by statistical software for analysis.Results To compare the mean values of Standard ADC、Dslow、Dfast and FF between normal liver and hepatocellular carcinoma,respectively.All have statistical significance(P values:0.006、0.001、0.013、0.004,P<0.05).The ROC analysizes the mean values of FF、Dfast、Standard ADC and Dslow for hepatocellular carcinoma.Results show that the area under the ROC curves are 0.728、0.730、0.730 and 0.787,respectively.Use the Pearson correlation to analysize between Standard ADC、Dslow、Dfast、FF.Results show that there were some positive correlations between Standard ADC and Dslow,Standard ADC and Dfast,respectively.By further analyzing the difference between Standard ADC of normal liver and hepatocellular carcinoma and Dslow,respectively.Results showed that had statistical significance(p values:0.001、0.000,P<0.05).Conclusion Mono-exponential model and bi-exponential model DWI both could be used for quantitative analysis of HCC.But the bi-exponential model could reflect the tissue of the internal molecular diffusion movement and microcirculation perfusion.Especially,Dslow is higher in HCC diagnosis.Therefore,bi-exponential model could provide more accurate information than mono-exponential model l in the diagnosis of hepatocellular carcinoma.Part ⅡObjective Because of the complexity of biological tissues of molecular motion and high b values(b>1000s/mm2)diffusion weighted imaging.The signal attenuation of DWI can show multi-index model.In order to describe the characteristics of water molecules motion accurately.Then,some scholars put forward stretched-exponential model.So far,there are few literatures reported stretched-exponential model which were applied in hepatic lesions.And the comparison between mono-exponential model and stretched-exponential model of DWI was reported less.Therefore,the purpose of this study was to investigate the technique of mono-exponential model and stretched-exponential model of DWI which applied in the diagnosis of hepatocellular carcinoma.Method The methods are same with the part Ⅰ.Results To compare the mean values of Standard ADC,DDC and α between normal liver and hepatocellular carcinoma,respectively.All have statistical significance(p values: 0.006、0.000、0.000,P <0.05).The ROC analysizes the mean values of Standard ADC、α、DDC for hepatocellular carcinoma.Results show that the area under the ROC curves are0.732、0.768、0.872,respectively.Use the Pearson correlation to analysize between Standard ADC,DDC,α.Results show that there are some positive correlations between Standard ADC and DDC.By further analyzing the difference between Standard ADC of normal liver and hepatocellular carcinoma and DDC,respectively.Results showed that had statistical significance(p values: 0.000、0.000,P <0.05).Coclusion Mono-exponential model and stretched-exponential model DWI both could be used for quantitative analysis of HCC.But when using a higher value of b(>1000 s/b was)DWI and the complex of tissue.The signal intensity attenuation would follow multi-exponential model.It was stretched-exponential model.Especially,the stretched-exponential model(DDC,alpha)in the diagnosis of hepatocellular carcinoma were higher than the mono-exponential model(ADC).Therefore,stretched-exponential model could provide new and more comprehensive information than mono-exponential model in the diagnosis of hepatocellular carcinoma.Part ⅢObjective DWI plays an important clinical value in tumor diagnosis curative effect and follow-up.But they were based on traditional mono-exponential model.So far,there are few literatures reported bi-exponential model,stretched-exponential model of DWI in the liver lesions.And comparing the two models was less reported.Therefore,the purpose of this study was to investigate the technique of bi-exponential model and stretched-exponential model of DWI which applied in the diagnosis of hepatocellular carcinoma.Method The methods are same with the part Ⅰ.Results To compare the mean values of Dslow,Dfast,FF,DDC and α between normal liver and hepatocellular carcinoma,respectively.All have statistical significance(p values:0.001、0.013、0.004、0.000、0.000,P <0.05).The ROC analysizes the mean values of FF、Dfast、α、Dslow、DDC for hepatocellular carcinoma.Results show that the area under the ROC curves are 0.728、0.730、0.768、0.787、0.872,respectively.Use the Pearson correlation to analysize between Dslow,Dfast,FF,DDC and α.Results show that there are some negative correlations between Dfast and α.By further analyzing the difference between Dslow of normal liver and hepatocellular carcinoma and DDC,respectively.Results showed that had statistical significance(p values: 0.000、0.000,P <0.05).Coclusion Compared bi-exponential model and stretched-exponential model of DWI.On the one hand,overcome the faults of bi-exponential model including the fast(perfusion)and slow(dispersion)two diffusion components.While the stretched-exponential model takes into account the complexity of the molecular motion in the tissue.On the other hand,the fitting stability of stretched-exponential model is higher.Especially the parameters of stretched-exponential model diagnose higher.And it introduces a new parameter.Therefore,stretched-exponential model could provide new and more accurate information than bi-exponential model.It will become a new means of cancer detection and evaluation.