Application Of Whole-Volume Apparent Diffusion Coefficient Histogram Of Rectal Adenocarcinoma In Preoperative Staging And Therapeutic Effect Evaluation Under Chemo-radiotherapy

Part Ⅰ:Application of Whole-Volume Apparent Diffusion Coefficient Histogram in Staging of Rectal AdenocarcinomaObjective:To investigate the efficacy of histogram analysis of the whole-volume in apparent diffusion coef ficient(ADC)for T and N staging in rectal adenocarcinomaMaterials and Methods:Thirty-five patients were enrolled in and underwent preoperative DWI examination.Tumors were delineated on each slice of the DWI images,each ROI was automatically synchronized with the ROI on the corresponding ADC maps,and all the ROIs made up the VOI.A series of histogram parameters were calculated according VOI and correlated with T and N staging by Spearman correlation analysis.The diagnostic performance of each parameter for distinguishing T and N staging was assessed by using the area under the receiver operating characteristic curve(AUC).The intraclass correlation coefficient(ICC)was calculated to assess the repeatability between observersResults:There were significant correlations between histogram parameters(histogram width and skew)and T-staging(r=0.355,P=0.036;r=0.361,P=0.033)Among all the histogram parameters,histogram width and skew had larger AUC values in differentiating T3 from T1/2 tumor,which were 0.716 and 0.720 respectively(P=0.049,0.045).However,we didn’t find any positive result in whether lymph node was involved.The ICC of ADCmean,ADC5%-90%,histogram width,skew and kurtosis were more than 0.8 in repeatability test.Conclusion:The repeatability of ADCmean,ADC5%-90%,histogram width,skew and kurtosis in rectal adenocarcinoma was high.Histogram width and skew could distinguish T3 from other stages of rectal adenocarcinoma.Part Ⅱ:Application of Whole-Volume Apparent Diffusion Coefficient Histogram in Therapeutic Effect Evaluation of Advanced Rectal Adenocarcinoma under Chemo-radiotherapyObjective:To investigate the changes of parameters of the whole-volume apparent diffusion coefficient(ADC)histogram between before and after chemo-radiotherapy(CRT)in advanced rectal adenocarcinoma.Materials and Methods:Fifteen patients were enrolled in,they all underwent DWI examination before starting therapy and after CRT.Tumors were delineated on each slice of the DWI images,each ROI was automatically synchronized with the ROI on the corresponding ADC maps,and all the ROIs made up the VOI.A series of histogram parameters were calculated according VOI.Shapiro-Wilk test was used to check the normality of all ADC histogram parameters in different therapeutic groups.Wilcoxon’s test was used to find the changes of parameters between before and after CRT.Mann-whitney U test was used to different parameters between different groups before starting therapy and after CRT.Results:The value of ADCmean,ADCmin,ADC5%-90%and mode increased while kurtosis and entropy decreased significantly after CRT(P<0.05).The changes of entropy in the group of CR were higher than in non-CR group apparently after CRT(P=0.026).Conclusion:ADCmean,ADCmin,ADC5%-90%,mode,kurtosis and entropy changed obviously after CRT in advanced rectal adenocarcinoma,and the changes of entropy in CR group is higher than in non-CR.