| Objective:To investigate the volumetric ROI histogram of D mono,D*mono and f mono derived from the intravoxel incoherent motion(IVIM)to preoperatively evaluate the pathological differentiation of hepatocellular carcinoma(HCC)Materials and Methods:We retrospectively analyzed 51 HCC patients(52 HCC lesions)confirmed by pathology(biopsy or postoperative paraffin embedding)aged between 31 to 76 years old,60.77 ± 8.95 years old,including 41 males and 10 females,who underwent 3.0 Tesla magnetic resonance imaging from July 2015 to May 2019 in our hospital.The pathological results of " poorly-moderately differentiated,poorly differentiated HCC lesions" were categorized as poorly differentiated HCC groups,and"well differentiated,well-moderately differentiated,moderately differentiated HCC lesions" were categorized as non-poorly differentiated HCC groups.Finally,there were 15 HCC lesions in the poorly differentiated HCC group(poorly-moderately differentiated number=8,poorly differentiated number=7),and 37 HCC lesions in the non-poorly differentiated HCC group(well differentiated number=9,well-moderately differentiation number=13,moderately differentiated number=15).All patients underwent a 3.0T(GE-Signa HDXT)magnetic resonance scan before surgery.The scan sequences included T1 WI,T2WI,LAVA dynamic enhanced scan(plain scan,early arterial,advanced arterial,portal venous,and equilibrated phase),DWI(b=0,600s/mm2)and IVIM(b=0,20,50,100,150,200,400,800,1200,2000,3000 s/mm2).The DWI and IVIM images were transmitted to the GE AW4.6 workstation.The DWI images were post-processed to obtain the apparent diffusion coefficient(ADC)map and the IVIM images were post-processed to obtain three parameter maps of two-order single exponential model,which were slow apparent diffusion coefficient mono(D mono),fast diffusion coefficient mono(D*mono)and perfusion fraction mono(f mono).Volume ROI histogram analysis:ADC?D mono?D*mono?f mono maps were imported into the Omni-Kinetics software.Taking the contours of the high signal region of the lesion on DWI(b=600 s/mm2)images as the reference standard in the Omni-Kinetics software,the ROI was delineated at each level of the lesion on the ADC image,and then these ROIs were merged into one volume ROI;Taking the contours of the high signal region of the IVIM(b=200 s/mm2)image of the lesion as the reference standard,the ROI were delineated at each level of the lesion on the D mono,D*mono,and f mono images,and then these ROIs were merged into one volume ROI.ROIs delineation should include HCC necrosis,hemorrhage,cystic zone,and avoid the bile ducts and main blood vessels visible to the naked eye as much as possible.The parameters of the histogram of the volume ROI of the ADC,D mono,D*mono,and f mono values were respectively calculated,including the minimum value(min),the maximum value(max),and the mean(mean),standard deviation(std),variance(var),range,skewness,kurtosis,percentile quantile(5th,10th,25th,50th,75th,90th,95th).Traditional ROI analysis:On the AW4.6 workstation,the HCC lesions on the ADC,D mono,D*mono,and f mono images were measured with a circular ROI of three equal areas(in order that the area of the ROIs are the same,the replication method of ROI are applicated).When ROI was delineated,we should exclude necrosis,hemorrhage,cystic change,bile ducts and large blood vessels visible to the naked eye of HCC lesions.The average level of the three ROI values were calculated.One month later the above-described volume ROI histogram and the traditional ROI delineation process and calculation process were repeated by the author.ICC test were used to evaluated the consistency of two assessments(pre-assessment and pro-assessment).If the consistency was good,the average value of the two assessment results(pre-assessment and pro-assessment)was taken for subsequent statistical analysis.Independent sample student t-tests or Mann-Whitney U test were used to compare the differences between the two groups of HCC volume ROI histograms and traditional ROI values.The ROC curves were made,and then they were followed by the analysis and comparison of diagnostic performance.Results:(1)The volume ROI histogram and value of traditional ROI through pre-assessment and post-assessment were consistent by the same observer,and the ICC values were all greater than 0.75.(2)The ADC-range of poorly differentiated HCC was higher than that of non-poorly differentiated HCC {(1.650±0.734)×10-3mm2/s vs.(1.227±0.651)×10-3mm2/s,P<0.05}.There was no significant difference in residual histogram parameters of ADC between the two groups(P>0.05).(3)D mono-min;mean;5th;10th;25th;50th of poorly differentiated HCC was lower than that of non-poorly differentiated HCC {(0.134±0.191)×10-3mm2/s vs.(0.319±0.142)×10-3mm2/s;0.539±0.106)×10-3mm2/s vs.(0.613±0.114)×10-3mm2/s;(0.332±0.101)×10-3mm2/s vs.(0.451±10.119)×10-3mm2/s;(0.380±0.093)×10-3mm2/s vs.(0.488±0.118)×10-3mm2/s;[0.481(0.364,0.523)]×0-3mm2/s vs.[0.552(0.464,0.631)]×10-3mm2/s(0.539±0.109)×10-3mm2/s vs.(0.618 ± 0.115)×10-3mm2/s;P<0.05}.D mono-std;range of poorly differentiated HCC was higher than that of non-poorly HCC {(0.128±0.055)×10-3mm2/s vs.(0.095±0.031)×10-3mm2/s;(0.785±0.333)×10-3mm2/s vs.(0.537±0.216)×10-3mm2/s,P<0.05}.There was no significant difference in residual histogram parameters of D mono between the two groups(P>0.05).(4)D*mono-min of poorly differentiated HCC was lower than that of non-poorly differentiated HCC {[-34.520(-37.140,0.340)]×10-3mm2/s vs.[0.540(-3.265,1.563)]×10-3mm2/s,P<0.05}.There was no significant difference in residual histogram parameters of D*mono between the two groups(P>0.05).(5)The f mono-min of poorly differentiated HCC was lower than that of non-poorly differentiated HCC {[(0.000(0.000,16.485)]%and[(14.290(0.000,25.915)]%,P<0.05}.There was no significant difference in residual histogram parameters of f mono between the two groups(P>0.05).(6)The traditional ROI value of D mono of poorly differentiated HCC was lower than that of non-lowly differentiated HCC {(0.541±0.115)×10-3mm2/s vs.(0.624±0.133)×10-3mm2/s,P<0.05}.There was no significant difference in traditional ROI value of ADC,D*mono,and f mono between the two groups(P>0.05).(7)The min value of the histogram was negative due to the influence of image noise,which is not logical.Therefore,the diagnostic performance of the min value of the histogram was not analyzed in subsequent statistical analysis.(8)The AUC(area under the ROC curve),diagnostic boundary value,sensitivity and specificity of ADC-range for the diagnosis of poorly differentiated HCC were 0.668,?1.202×10-3 mm2/s,80.0%,54.1%respectively.(9)The AUC,diagnostic boundary value,sensitivity and specificity of D mono-mean;-5th;-10th;-25th;-50th for the diagnosis of poorly differentiated HCC was 0.672,?0.617×10-3 mm2/s,80.0%,51.4%;0.778,?0.363×10-3 mm2/s,66.7%,78.4%;0.768,?0.479×10-3 mm2/s,93.3%,51.4%;0.721,?0.534×10-3 mm2/s,86.7%,59.5%;0.679,?0.638×10-3 mm2/s,86.7%,45.9%respectively.The AUC,diagnostic boundary value,sensitivity and specificity of D mono-std;range for the diagnosis of poorly differentiated HCC was 0.667,?0.166×10-3 mm2/s,40.0%,97.3%;0.737,?0.624×10-3 mm2/s,73.3%,75.7%.(10)The AUC,diagnostic boundary value,sensitivity,and specificity of the D mono traditional ROI for the diagnosis of poorly differentiated HCC was 0.675,?0.527×10-3 mm2/s,53.3%,and 81.1%,respectively.(11)There was no significant difference in the volumetric ROI histogram between the conventional ROI and the AUC value of the ROC curve for the diagnosis of poorly differentiated HCC(P>0.05).Conclusions:The volume ROI histograms of ADC derived from DWI and the D mono derived from IVIM are helpful for the preoperative pathological differentiation of HCC.Although the diagnostic performance of volume ROI histogram is similar to that of traditional ROI,the volume ROI histogram provides more diagnostic parameters to reflects tumor heterogeneity. |
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