The Value Of Diffusion-weighted Imaging With Single Index And Double Index And Histogram Analysis Of Their Parameter Maps In The Diagnosis Of Prostate Cancer

Objective:To explore the value of ultra-high b value diffusion-weighted imaging(DWI),intravoxel incoherent motion(IVIM)imaging and histogram analysis of their parameter maps in the differential diagnosis of prostate cancer(PCa)and benign prostate hyperplasia(BPH),as well as the value of predicting the aggressiveness and differentiation degree of PCa.Methods:A total of 73 patients who had prostate IVIM-DWI(b=0,50,100,150,200,400,600,800,1000,1500,2000s/mm2)in People's Hospital of Sichuan Province from November 2018 to December 2019 and subsequently diagnosed as PCa or benign prostatic hyperplasia(BPH)by transrectal ultrasound-guided biopsy or surgical pathology were collected Prospectively as the study subjects.According to the pathological results and the signal characteristics of MRI images,especially the characteristics of axial T2WI and DWI images,all the patients were delineated the areas of interest(ROI)on the corresponding parameter maps.ADC value(b=50,2000s/mm2),IVIM imaging parameters(b=0?600s/mm2)D value,D,value and f value and histogram indexs of each parameter map such as mean,variance,skewness,kurtosis,percentiles(1%,10%,50%,90%,99%)of the PCa group and BPH group were compared.The receiver operating characteristic curves(ROC)of the parameters with statistically significant differences were drawn to obtain the corresponding threshold values for differential diagnosis of PCa and BPH and to compare their diagnostic effectiveness.The PCa patients was subdivided into the low-grade group(LG,Gleason score<3+4)and the high-grade group(HG,Gleason score>4+3)according to the Gleason scoring system,and the inter-group differences of the above parameters were compared.The ROC curves of the parameters with statistically significant differences were drawn to obtain the corresponding threshold values in distinguishing the differentiation degrees of PCa and to compare their diagnostic effectiveness.The correlation between each parameter in PCa group and Gleason score was analyzed.Results:? In the PCa group,45 patients were aged from 51.0 to 92.0 years,with an average age of 72.5±7.9 years.Prostate specific antigen(PSA)levels ranged from 4.1 to 1000.Ong/ml,with a median PSA level of 83.5ng/ml(31.1ng/ml,255.5ng/ml).In the BPH group,28 patients were aged from 59.0-90.0 years,with an average age of 72.5±8.1 years.PSA level ranged from 2.0 to 45.0ng/ml,with an average PSA level of 15.6±11.8ng/ml.The age difference between PCa group and BPH group was not statistically significant(P>0.05).The PSA level of PCa group was higher than that of BPH group,and the difference was statistically significant(P<0.05).According to Gleason score,prostate cancer patients were divided into LG group and HG group,with 13 cases and 32 cases respectively.?The lesions of patients with PCa presented homogeneous or inhomogeneous low signal on T2WI images,significantly high signal on DWI images,significantly low signal on ADC and D maps,mixed signal on D*and f maps due to the low resolution.In patients with BPH,T2WI images showed the central glandular regions(including transitional zone,periurethral gland and central zone)scattered with high,equal and low mixed signal nodules in all cases.The DWI images of 17 cases presented equal signal,while ADC and D maps presented equal signal.The DWI images of 11 cases presented slightly higher signal,while ADC and D maps presented slightly lower signal.All the cases prsented equal and low mixed signal on D*and f maps due to the low resolution.?The differences of parameters between PCa group and BPH group were compared.The results showed that the average ADC value and average D value of PCa group were lower than that of BPH group,and the average f value was higher than that of BPH group,all the differences were statistically significant(P<0.05).The comparison results of histogram indexes of parameter maps showed that all histogram parameters of ADC and D maps and partial histogram parameters of D*map showed statistically significant differences between the two groups(P<0.05),Which ADCvariance,ADCskewness,ADCkurtosis,Dvariance,Dske wness and Dkurtosis in PCa group were higher than that of BPH group,while the remaining parameters of ADC and D maps group were lower than that of BPH group,D*variance and D*99%in PCa group were higher than that in BPH group.The ROC curves of the above parameters were drawn to obtain the corresponding threshold values in differential diagnosis of PCa and to compare their diagnostic effectiveness.The results showed that the areas under curve(AUC)and diagnostic thresholds of average ADC value,average D value and average f value in differential diagnosis of PCa were 0.983 and 0.8×10-3 mm2/s,0.994 and 0.95×10-3mm2/s,0.752 and 0.1,respectively.The AUCs and diagnostic thresholds of ADCmean,ADCvariance,ADCskewness,ADCkurtosis,ADC1%,ADC10%,ADC50%,ADC90%and ADC99%were 0.933 and 151.36,0.721 and 242.73,0.757 and 0.16,0.668 and 0.16,0.963 and 107,0.948 and 115,0.933 and 151,0.887 and 155,0.843 and 177,respectively.The AUCs and diagnostic thresholds of Dmean,Dvariance,Dskewness,Dkurtosis,D1%,D10%,D50%,D90%and D99%were 0.972 and 69.94,0.706 and 286.45,0.834 and 0.36,0.724 and 0.26,0.972 and 39,0.985 and 55,0.972 and 70,0.919 and 95,0.781 and 115,respectively.The AUCs and diagnostic thresholds of D*variance,D*99%were 0.698 and 393.70,0.654 and 91,respectively The parameters with high diagnostic performance(AUC>0.9)included average ADC value,average D value,ADCmean,ADC1%,ADC10%,ADC50%,Dmean,D1%,D10%,D50%and D90%.The AUC of D90%was lower than that of average ADC value,average D value,Dmean,,D10%,and D50%,respectively(P<0.05),and there were no significant differences in AUCs between the remaining parameters with high diagnostic effectiveness(P>0.05).?The differences of parameters between LG group and HG group were compared.The results showed that the average ADC value and average D value of the LG group were significantly higher than that of the HG group,while the average f value was significantly lower than that of the HG group(P<0.05).The comparison results of histogram indexes of parameter maps showed that most histogram parameters of ADC and D maps and some histogram parameters of f map showed statistically significant differences between the two groups(P<0.05),Which the ADCmean,ADC0%,ADC10%,ADC50%,ADC90%,ADC99%,Dmean,D10%,D50%and D90%in LG group were higher than that in HG group,while Dskewness,Dkurtosis,fvariance and f50%were lower than that in HG group.The ROC curves of above parameters were drawn to obtain the corresponding threshold values in distinguishing the differentiation degrees of PCa and to compare their diagnostic effectiveness The results showed that the AUCs and diagnostic thresholds of average ADC value,average D value and average f value in distinguishing differentiation degrees of PCa were 0.885 and 0.63×10-3 mm2/s,0.883 and 0.78×10-3mm2/s,0.707 and 0.13,respectively.The AUCs and diagnostic thresholds of ADCmean,ADC1%,ADC10%,ADC50%,ADC90%and ADC99%were 0.776 and 110.97,0.798 and 81,0.754 and 91,0.756 and 108,0.764 and 139,0.721 and 159,respectively.The AUCs and diagnostic thresholds of Dmean,Dskewness,Dkurtosis,D10%,D50%and D90%were 0.743 and 59.48,0.786 and 0.75,0.834 and 0.35,0.688 and 46,0.754 and 55,0.744 and 78,respectively.The AUCs and diagnostic thresholds of fvariance,f50%were 0.695 and 312.56,0.665 and 34,respectively.The diagnostic performance of average ADC value,average D value and Dkurtosis in the above parameters was relatively high(AUC>0.8),and there was no significant differences among the three AUCs(P>0.05).By logistic regression analysis,the AUC of the ROC curve combined average D value,average f value and D90%was 0.950,Which was significantly higher than the AUCs of independent parameters(P<0.05).?Spearman correlation analysis was used to evaluate the correlation between each parameter in PCa group and Gleason score.The results showed that the correlation coefficients(r)between the average ADC value,the average D value and the average f value and Gleason score were-0.682,-0.554 and 0.364,respectively(P<0.05).Analysis results of histogram indexs of the parameter maps showed that the ADCmean,ADC1%,ADC10%,ADC50%,ADC90%and D50%were negatively correlated with Gleason score,while Dskewness,Dkurtosis,D*kurtosis,fvariance,fkurtosis,f99%were positively correlated with Gleason score(P<0.05),and the r absolute values of the above parameters ranged from 0.3 to 0.5.Conclusions:?The ultra-high b value DWI parameter ADC value,IVIM imaging parameters D value and f value can differentiate PCa from BPH.ADC value and D value have high diagnostic performance,and their diagnostic accuracy is equivalent.?All histogram parameters of ADC and D maps and some histogram parameters of D'map can differentiate PCa from BPH.The diagnostic performance of ADCmean,ADC1%,ADC10%,ADC50%,Dmean,,D10%and D50%was higher,which was equivalent to that of avrage ADC value and average D value.Histogram parameters can provide more information to reflect the heterogeneity within the tumor,and the diagnostic accuracy is similar to the conventional parameters.?ADC value,D value and f value can distinguish PCa with different differentiation degrees.Most histogram parameters of ADC and D maps and some histogram parameters of f map can distinguish PCa with different degrees of differentiation.Dkurtosis has the relatively high diagnostic performance,which is equivalent to that of average ADC value and average D value.The accuracy of predicting differentiation degrees of PCa by combining average D value,average f value and D90%was higher than that by independent parameters.In terms of predicting the differentiation degrees and invasiveness of PCa,histogram parameters can not only provide more information to reflect the heterogeneity within the tumor,but also improve the accuracy of diagnosis when combined with conventional parameters.?ADC value and D value were moderately negatively correlated with Gleason score,while f value was low positively correlated with Gleason score.The ADCmean,ADC1%,ADC10%,ADC50%,ADC90%and D50%were low negatively correlated with Gleason score,while Dskewness,Dkurtosis,D*kurtosis,fvariance,(kurtosis and f99%were low positively correlated with Gleason score.