Comparative Study Of Extended Tofts Model And Reference Region Model In Prostate Cancer By Applying DCE-MRI

ObjectiveTo assess the value of the Extended Tofts and Reference Region Model?RRM?in diagnosing prostate cancer?PC?with vascular function parameters calculated by the two models,and to evaluate the correlation between parameters and PSAD.Materials and Methods31 patients with PC confirmed by TRUS or surgical pathology underwent MRI routine sequence and DCE-MRI,Extended Tofts Model and RRM in Omni Kinetics Manual software developed by GE company were used to obtain parameters Ktrans?the volume transfer constant from plasma to the extracellular extravascular space??Ve?the ratio of the EES volume to tissue volume??Kep?the efflux rate constant from EES back to plasma?and Vp?the ratio of the blood plasma volume to tissue volume?in PC.and normal tissue.Perfusion parameters obtained with the Extended Tofts model and RRM in prostate cancer and normal tissue were compared by using Wilcoxon tests.The diagnostic efficacy of parameters for prostate cancer was assessed using receiver operating characteristic curve?ROC curve?.Spearman correlation coefficient was used to express correlation between parameters and PSA.P values below 0.05 were considered to indicate a statistically significant difference.Results1.For Extended Tofts model,parameters Ktrans?Kep?Vp and Ve were?0.338±0.157?min-1??1.678±0.866?min-1;0.014±0.030.0.234±0.119 respectively.For RRM,parameters Ktrans?Kep and Vp were?3.233±1.650?min-1??1.126±0.885?min-1?1.088±0.720.2.Both the Extended Tofts model and RR model produced parameters Ktrans?Kep and Vp with significant differences in PC when compared to normal tissue?p<0.05?3.The sensitivity and specificity of Ktrans,Kep diagnosing PC for Extended Tofts model were higher when compared to RRM?Ktrans were 91.8%.85.7%,89.8%.81%and Kep were 93.9%.95.2%,67.3%.81%respectively?.The sensitivity and specificity of Vp diagnosing PC for Extended Tofts model were lower when compared to RRM?Vp were 38.8%?81.2%;75.5%?0.85.7%respectively?.4.For the Extended Tofts model,the parameter Ktrans was positively correlated with Kep and Ve.?r=0.438?0.511,respectively?,and a negative correlation between Ktrans and Ve?r=-0.561?;For RRM,the parameter Ktrans was positively correlated with Kep and Ve.?r=0.624?0.451,respectively?..The parameter Ktrans estimated by the Extended Tofts model was positively correlated with Ktrans estimated by the RRM?r=0.327?.5.In the Extended Tofts model,PSAD was correlated with Kep and Ve?r=--0.414,0.420,respectively?.No correlation was found between PSAD and parameters in RRM.ConclusionThe Extended Tofts model is more suitable for the diagnosis of PC,Ktrans and Kep,and PSAD are especially correlated with K_ep and V_e in Extended Tofts model.