ABSTRACT
[Objective]To investigate the diagnostic value of quantitative perfusion parameters of dynamic contrast-enhanced im?aging for discriminating metastatic from non-metastatic regional lymph nodes in rectal cancer.[Methods]122 patients of our depart?ment were collected from 2015.01 to 2016.08, and 203 lymph nodes, including metastatic lymph nodes (MLNs, n=95) and non-meta?static lymph nodes (NMLNs, n=108), were analyzed. The short-axis diameter (S), long-axis diameter (L), short-to long-axis diameter ratio (S/L), volume transfer constant (Ktrans), rate constant (Kep) and extravascular extracellular space (EES) fractional volume (Ve) were compared between two groups respectively. Then using S=5 mm as a cutoff value, these parameters were compared between subgroups. Receive operating characteristic curve (ROC) was used to analyze the diagnostic efficiency and find the optimal cutoff values.[Re?sults]The metastatic group exhibited higher S and L, but lower S/L, Ktrans and Kep than the non-metastatic group (P<0.01). However, the Ve did not differ significantly between two groups (P=0.308). Optimal cutoff values [area under the curve (AUC), sensitivity, speci?ficity] of Ktrans for discriminate metastatic lymph nodes from non-metastatic were 0.088 min-1 (0.69, 58.3%, 78.9%). When S>/=5 mm, subgroup analysis revealed that Ktrans and Kep of MLNs were significant higher than those of NMLNs (P<0.001), but Ve was lower (P=0.039). Optimal cutoff values (AUC, sensitivity, specificity) of Ktrans were 0.088 min-1 (0.675, 57.1%, 77.9%). However, when S<5 mm, MLNs showed lower Ktrans than NMLNs (P=0.001), but there were no significantly statistic differences of Kep and Ve between these two groups (P>0.1). Optimal cutoff values (AUC, sensitivity, specificity) of Ktrans were 0.087 min-1 (0.732, 60.5%, 81.5%).[Conclusion]Ktrans can be used to discriminate regional MLNs from NMLNs in rectal cancer, especially when the short-axis diameter is less than 5 millimeters.