The Value Of Different DWI Models In The Diagnosis Of Prostate Cancer And The Evaluation Of Its Pathological Stage

Objective:To explore the diagnostic value of various parameters of mono-exponential(ADC),bi-exponential(D,D*,f)and stretched exponential(α,DDC)diffusion-weighted imaging(DWI)model ofprostate cancer(PCa),and further evaluate the risk classification of PCa and the correlation with Gleason score.Materials and methods:Sixty-seven patients who underwent prostate MR examination and were divided into PCa group and BPH group in our hospital from June 2021 to December 2021 were collected,including 32 cases of PCa groupand 35 cases of BPHgroup.All participants underwent conventional axial T1WI,T2WI,and multi-b-value DWI examinations.Images were post-processed,and the parameters of the mono-exponential,bi-exponential,as well as stretched-exponential model DWI were measured respectively and compared with the difference between the PCa group and BPH group.The ROC curvewas used to compare the role of statistically significant parameters in the differential diagnosis of PCa and BPH and the optimal diagnostic threshold for parameters was calculated.The PCa was classified as low-risk group,indeterminate risk group and high-risk group according to Gleason scores.The differences of parameters among the three groups were compared,and the relationship between those parameters and Gleason score was evaluated.Results:1.ADC,D,F,αand DDC in the PCa groupwere lower than those in the BPH group,and the difference between the two groups was statistically significant(P<0.05).The D*in PCa groupwas slightly higher than in BPH group,and there was no significant difference between the two groups(P=0.151).2.ADC,D,DDC and f have higher diagnostic efficacy for PCa.The area under the curve(AUC)values of ADC,D,f and DDCwere 0.982,0.989,0.907and 0.991 respectively.There was no statistically significant difference in the area under the curve of ADC,D and DDC.the diagnostic thresholds were 0.907×10-3mm2/s,0.814×10-3mm2/s,0.289and 1.143×10-3mm2/s.3.The values of ADC,Dand DDC were statistically significantly differences among the three groups.f and α were statistically significant in the low-risk and high-risk groups.With the risk grading increased,the values of parameters tend to decrease.4.The D value was highly negatively correlated with the Gleason score(r=0.812,P<0.001).The ADC,f and DDC values of PCa were moderate negatively correlation with Gleason score(r=0.785,P<0.001;r=0.713,P<0.001;r=0.779,P<0.001).The a values of PCa were negatively correlated with Gleason score(r=0.412,P<0.001).Conclusions:1.Mono-exponential,bi-exponential,and stretched exponential model DWI have significant clinical value in the diagnosis of PCa and the evaluation of its pathological stage.Parameters which were associated with diffusion such as ADC,D,as well as DDC all showed good discrimination ability with the risk of PCa.2.Bi-exponential and stretched exponential model DWI provides more different types of quantitative information than conventional DWI and can better reflect the characteristics of PCa lesion interiors in many different aspects.furthermore,the biological information was reflected by different parameters complement each other.It is expected to improve the diagnostic efficiency of PCa and accurately evaluate its malignancy under noninvasive conditions.