Multiple Exponential Models Of Diffusion Weighted Imaging In Differentiating Hepatocellular Carcinoma From Hepatic Hemangioma

Objective: To evaluate the feasibility of the monoexponential model of diffusion-weighted imaging(DWI),biexponential and stretched-exponential models of intravoxel incoherent motion(IVIM)in differentiating hepatocellular carcinoma(HCC)from hepatic hemangioma(HH).Materials and Methods: Sixty six patients under MR liver scanning were retrospectively enrolled in our hospital from August 2015 to April 2016.With followed histopathological examination and/or clinical proof,30 lesions in 29 patients were confirmed as hepatocellular carcinoma(male 22,female 7,age from 35 to 79,mean age 57.93±9.94).From the imaging diagnosis,38 lesions in 37 patients were confirmed that hepatic hemangioma(male 14,female 23,age from 29 to 77,mean age 50.57±11.48).All the patients were performed MRI exams on an 1.5T scanner(GE-Signa HDXT,USA)in a protocol containing the routine T1 WI,T2WI,LAVA,DWI(b=0,600s/mm2),e DWI(b=0,20,50,100,150,200,400,800,1200,2000,3000s/mm2)and HB DWI(b=0,1500,2000,3000,4000s/mm2).The signal features,patterns of lesion border and the location of lesions of MR images were reviewed and analyzed by author and one experienced radiologist who has five years experience in abdominal diagnosis,the results could reach an agreement in different opinion through the consultation process,using a dedicated software in Functool on GE ADW4.4 workstation,and two observers were blinded to the results.For each region of interested(ROI),the mean value of DWI(ADC),e DWI(Standard ADC,D-mono,D~*-mono,fmono,D-Bi?D~*-Bi?fBi)and HB DWI(DDC,?)were measured.Two observers were not informed of the clinical information in independent reading analysis and measurement.The ROI were drawn three times in the tumor parenchyma that greater than 1/3 of the solid portion of tumor avoiding of part of hemorrhage,necrosis as much as possible,then the average value was calculated for further statistical analysis.All data were analysed with the SPSS 17.0 statistical software.Fisher's Exact Test was used to analysis the location of lesions,the Mann-Whitney test was executed to compare the size of lesions,Chi-square Test was used to analysis the signal condition of lesions and patterns of lesion border,there was a significant difference when P<0.05.ICC test was used to examine the consistency of the measurements between two observers,the average data from two observers were performed for further statistical analysis.If the parameters fitted normal distribution,the student's t-test was executed to compare the obtained parametric values,otherwise Mann-Whitney test was executed to compare the values,there was a significant difference when P<0.05.The ROC curves of all the parameters were drew and analyzed and the values concerned obvious difference(P < 0.05).Results: The size and location of lesions in HCC and HH group was no statistically significant difference(P>0.05).The signal condition in T1 WI,T2WI of lesions had statistically significant difference(P<0.05).The signal condition in DWI of lesions was no statistically significant difference(P>0.05).The patterns of lesion border remained statistically significant difference(P<0.05).The ICC value of the DWI parameter(ADC),e DWI parameters(Standard ADC,D~*-mono,D-mono,fmono,D~*-Bi,D-Bi,fBi)and HB DWI(DDC,?)in the HCC group and HH group were respectively,0.997,0.967,0.866,0.920,0.901,0.920,0.937,0.885,0.901,0.971 and 0.996,0.997,0.984,0.996, 0.983,0.993,0.981,0.977,0.967,0.988,exhibiting an amenable consistency.The ADC,standard ADC of HCC and HH were(1.38±0.41)×10-3mm2/s and(2.09±0.56)×10-3mm2/s?(0.96±0.51)×10-3mm2/s and(1.51±0.28)×10-3mm2/s.The D-mono,D~*-mono,fmono values of HCC and HH group were(0.64±0.14)×10-3mm2/s and(1.06±0.24)×10-3mm2/s?(13.95±7.53)×10-3mm2/s and(6.48±6.90)×10-3mm2/s?(0.44±0.02)and(0.70±0.02).The D-Bi,D~*-Bi,fBi values of them were(0.81±0.05)×10-3mm2/s and(1.68±0.17)×10-3mm2/s ?(51.94±34.20)×10-3mm2/s and(45.15±60.64)×10-3mm2/s?(0.39±0.14)and(0.50±0.21).The DDC values of HCC and HH were(7.29±1.30)×10-3mm2/s and(12.70±1.40)×10-3mm2/s,the results remained statistically significant(P<0.05).No statistically significant difference was observed between ? values of two groups(P>0.05).The area under the ROC curve of ADC,Standard ADC,D-mono,fmono,D-Bi were higher than 0.9,which was 0.912,0.987,0.976,0.903,0.906.The area under the ROC curve of D~*-mono was 0.849.The area under the ROC curve of D~*-Bi,fBi,DDC was 0.683,0.668,0.693,respectively.Conclusion:The signal conditions in T1 WI,T2WI and patterns of lesion border could help to differentiate from HCC to HH.The value of ADC,Standard ADC,D-mono,fmono,D-Bi have favorable effective functions for the diagnosis,Standard ADC from monoexponential model and D-mono from biexponential with multiple b values were significantly better than ADC from monoexponential model with single b value in differential diagnosis of hepatocellular carcinoma and hepatic hemangioma;D~*-mono,D~*-Bi,fBi and DDC value have certain ability to identify as a supplement for MR imaging with potential in diagnostic differentiation of hepatocellular carcinoma and hepatic hemangioma.