Objective To investigate the value of quantitative parameters of diffusion weighted imaging(DWI)based on mono-expo-nential model(MEM),diffusion kurtosis imaging(DKI)model,and stretched-exponential model(SEM)in predicting the efficacy of neoadjuvant therapy in locally advanced gastric cancer(LAGC).Methods Forty LAGC patients who underwent MRI examinations before neoadjuvant therapy and before radical surgery were prospectively enrolled.A radiologist delineated lesions on DWI images and acquired quantitative parameters before and after treatment,including lesion volume,apparent diffusion coefficient(ADC)of MEM,mean diffusivity(MD)and mean kurtosis(MK)of DKI model,distribution diffusion coefficient(DDC),and α of SEM.According to pathological tumor regression grade(TRG),the patients were stratified into good response group(TRG 0-1)and poor response group(TRG 2-3).The pre-treatment parameters and Δ of pre-and post-treatment parameters were compared between the two groups with Mann-Whitney U test;multivariate analysis was performed with binary logistic regression.Multiple DWI models and the combined model were established,and the prediction efficiency of each model was calculated.Results There was no significant differ-ence in each parameter before neoadjuvant therapy between the two groups(P>0.05).The delta of volume,ΔADC,ΔMD,and ΔDDC pre-and post-treatment were all statistically different between the two groups(P<0.05).The area under the curve(AUC)of ΔADC,ΔMD,and ΔDDC in predicting good response for LAGC were 0.900,0.806,and 0.762,respectively.The AUC of the combined model was 0.946.Conclusion Quantitative parameters of MEM,DKI model,and SEM can help predict the efficacy of neoadju-vant-treated LAGC patients.

Objective To investigate the value of quantitative parameters of diffusion weighted imaging(DWI)based on mono-expo-nential model(MEM),diffusion kurtosis imaging(DKI)model,and stretched-exponential model(SEM)in predicting the efficacy of neoadjuvant therapy in locally advanced gastric cancer(LAGC).Methods Forty LAGC patients who underwent MRI examinations before neoadjuvant therapy and before radical surgery were prospectively enrolled.A radiologist delineated lesions on DWI images and acquired quantitative parameters before and after treatment,including lesion volume,apparent diffusion coefficient(ADC)of MEM,mean diffusivity(MD)and mean kurtosis(MK)of DKI model,distribution diffusion coefficient(DDC),and α of SEM.According to pathological tumor regression grade(TRG),the patients were stratified into good response group(TRG 0-1)and poor response group(TRG 2-3).The pre-treatment parameters and Δ of pre-and post-treatment parameters were compared between the two groups with Mann-Whitney U test;multivariate analysis was performed with binary logistic regression.Multiple DWI models and the combined model were established,and the prediction efficiency of each model was calculated.Results There was no significant differ-ence in each parameter before neoadjuvant therapy between the two groups(P>0.05).The delta of volume,ΔADC,ΔMD,and ΔDDC pre-and post-treatment were all statistically different between the two groups(P<0.05).The area under the curve(AUC)of ΔADC,ΔMD,and ΔDDC in predicting good response for LAGC were 0.900,0.806,and 0.762,respectively.The AUC of the combined model was 0.946.Conclusion Quantitative parameters of MEM,DKI model,and SEM can help predict the efficacy of neoadju-vant-treated LAGC patients.