Purpose: To assess the role of perfusion-related signal decay on diffusion kurtosis imaging (DKI) estimates for in vivo stratification of glioma according to the integrated approach of the 2016 World Health Organization classification of tumors of the central nervous system (2016 CNS WHO).
Methods: In this study 77 patients with histopathologically confirmed glioma were retrospectively assessed between January 2013 and February 2017 in a prospective trial. Mean kurtosis (MK) and mean diffusivity (MD) metrics from DKI were assessed by two physicians blinded to the study from a volume of interest around the entire solid tumor. Wilcoxon's signed-rank test compared perfusion-biased and perfusion-corrected MK (MKpb and MKpc) and MD (MDpb, MDpc) values. One-way ANOVA was used to compare MKpb&pc and MDpb&pc values between 2016 WHO glioma grades. Spearman's correlation coefficient was used to correlate them with 2016 WHO glioma grades. Receiver operating characteristic (ROC) analysis was performed on MKpb&pc and MDpb&pc for the significant results.
Results: The MKpc values were significantly higher than MKpb values (p < 0.001), whereas MDpc values were significantly lower than MDpb values (p < 0.001). For stratifying gliomas, MKpb values (ROC AUC range, 0.818-0.979) showed a higher diagnostic performance than MKpc values (ROC AUC range, 0.773-0.975), whereas MDpb values (ROC AUC range, 0.744-0.928) showed less diagnostic performance than MDpc values (ROC AUC range, 0.753-0.934). The diagnostic accuracy of MKpb was 80.0%.
Conclusion: The MK and MD estimates of DKI are influenced by microcapillary blood perfusion; however, taking the effect of perfusion on DKI metrics into account does not substantially impact their overall diagnostic performance in classifying glioma according to the 2016 CNS WHO.
Keywords: Classification; Diffusion; Glioma; Perfusion; World Health Organization.