[Objective]To evaluate the diagnostic value of quantitative diffusion kurtosis imaging(DKI)parameters in discriminating metastatic from non-metastatic regional lymph nodes in rectal cancer.[Methods]Totally 116 patients who underwent preoperative DKI scanning and radical rectal cancer surgery without neoadjuvant therapy between January 2015 and August 2016,and 285 lymph nodes,including metastatic lymph nodes(MLNs,n=104)and non-metastatic lymph nodes(NMLNs,n=181),were analyzed.The short-axis diameter(S),apparent diffusion coefficient(ADC),mean kurtosis coefficient(MK),and mean diffusion coefficient(MD)were compared between the two groups,with S=5.5 mm as a cutoff value.Receiver operating characteristic(ROC)curves were utilized to assess diagnostic efficiency and determine optimal cutoff values.[Results]Metastatic lymph nodes exhibited significantly higher S,ADC,and MD values(P＜0.05),but markedly lower MK values(P＜0.01)compared with non-metastatic lymph nodes.The optimal cutoff values for MK[area under the curve(AUC),sensitivity,specificity]in discriminating metastatic from non-metastatic lymph nodes were 1.150(0.634,80.77%,45.86%).Subgroup analysis revealed that when S≥5.5 mm,MK was lower in metastatic lymph nodes than in non-metastatic nodes(P=0.037),with optimal cutoff values(AUC,sensitivity,specificity)of 1.213(0.604,87.50%,36.51%).No significant differences were observed in S,ADC,or MD between the groups(P＞0.05).When S＜5.5 mm,metastatic lymph nodes showed higher ADC and MD but lower MK than non-metastatic nodes(P＜0.05).The optimal cutoff values(AUC,sensitivity,specificity)for MK in this subgroup were 1.108(0.655,81.25%,55.93%).No significant difference in S was observed(P=0.097).[Conclusion]The DKI quantitative parameter MK can effectively discriminate regional MLNs from NMLNs in rectal cancer.Combining S with MK may further enhance diagnostic accuracy.

[Objective]To evaluate the diagnostic value of quantitative diffusion kurtosis imaging(DKI)parameters in discriminating metastatic from non-metastatic regional lymph nodes in rectal cancer.[Methods]Totally 116 patients who underwent preoperative DKI scanning and radical rectal cancer surgery without neoadjuvant therapy between January 2015 and August 2016,and 285 lymph nodes,including metastatic lymph nodes(MLNs,n=104)and non-metastatic lymph nodes(NMLNs,n=181),were analyzed.The short-axis diameter(S),apparent diffusion coefficient(ADC),mean kurtosis coefficient(MK),and mean diffusion coefficient(MD)were compared between the two groups,with S=5.5 mm as a cutoff value.Receiver operating characteristic(ROC)curves were utilized to assess diagnostic efficiency and determine optimal cutoff values.[Results]Metastatic lymph nodes exhibited significantly higher S,ADC,and MD values(P＜0.05),but markedly lower MK values(P＜0.01)compared with non-metastatic lymph nodes.The optimal cutoff values for MK[area under the curve(AUC),sensitivity,specificity]in discriminating metastatic from non-metastatic lymph nodes were 1.150(0.634,80.77%,45.86%).Subgroup analysis revealed that when S≥5.5 mm,MK was lower in metastatic lymph nodes than in non-metastatic nodes(P=0.037),with optimal cutoff values(AUC,sensitivity,specificity)of 1.213(0.604,87.50%,36.51%).No significant differences were observed in S,ADC,or MD between the groups(P＞0.05).When S＜5.5 mm,metastatic lymph nodes showed higher ADC and MD but lower MK than non-metastatic nodes(P＜0.05).The optimal cutoff values(AUC,sensitivity,specificity)for MK in this subgroup were 1.108(0.655,81.25%,55.93%).No significant difference in S was observed(P=0.097).[Conclusion]The DKI quantitative parameter MK can effectively discriminate regional MLNs from NMLNs in rectal cancer.Combining S with MK may further enhance diagnostic accuracy.