RESUMO
RATIONALE AND OBJECTIVES: This study aimed to investigate whether volume transfer constant (Ktrans) and volume of extravascular extracellular space per unit volume of tissue (Ve) derived from dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) could quantitatively assess the tumor proliferation index (Ki-67) of gliomas noninvasively. MATERIALS AND METHODS: The preoperative DCE MRI data of 69 patients with pathologically confirmed glioma (28, 8, and 33 cases in grades â ¡, â ¢, and â £) were retrospectively reviewed. The maximal Ktrans and Ve were measured in the tumor body. The immunohistochemistry was used to detect the expression of Ki-67 proteins in glioma specimens. The Mann-Whitney U test was applied to analyze the differences in Ktrans, Ve, and Ki-67 index across histologically defined glioma grades. Spearman correlation was performed between Ktrans, Ve, and Ki-67 index. The receiver operating characteristic curve analysis was used to determine the cutoff values of Ktrans and Ve in distinguishing different Ki-67 index expression levels. RESULTS: Ktrans, Ve, and Ki-67 index of grade â ¡ (0.027 min-1, 0.065, 4.04%) were significantly lower than those of grade â ¢ (0.093 min-1, 0.297, 25.13%) and â £ (0.100 min-1, 0.299, 25.37%). Both Ktrans and Ve significantly correlated with the Ki-67 index in all tumors and high-grade gliomas (HGGs, grade â ¢ and â £). The receiver operating characteristic curve analysis revealed that the cutoff values for Ktrans (0.079 min-1) and Ve (0.249) provided the best combination of sensitivity and specificity to distinguish the gliomas with high Ki-67 index from those with low Ki-67 index. CONCLUSION: The DCE MRI-derived parameters were valuable in assessing the tumor cell proliferation in HGG noninvasively.