Intravoxel water diffusion heterogeneity imaging of human high-grade gliomas

This study aimed to determine the potential value of intravoxel water diffusion heterogeneity imaging for brain tumor characterization and evaluation of high-grade gliomas, by comparing an established heterogeneity index (alpha value) measured in human high-grade gliomas to those of normal appearing white and grey matter landmarks. Twenty patients with high-grade gliomas prospectively underwent diffusion-weighted magnetic resonance imaging using multiple b-values. The stretched-exponential model was used to generate alpha and distributed diffusion coefficient (DDC) maps. The alpha values and DDCs of the tumor and contralateral anatomic landmarks were measured in each patient. Differences between alpha values of tumors and landmark tissues were assessed using paired t-tests. Correlation between tumor alpha and tumor DDC was assessed using Pearson's correlation coefficient. Mean alpha of tumors was significantly lower than that of contralateral frontal white matter (p = 0.0249), basal ganglia (p < 0.0001), cortical grey matter (p < 0.0001), and centrum semiovale (p = 0.0497). Correlation between tumor alpha and tumor DDC was strongly negative (Pearson correlation coefficient, -0.8493; p < 0.0001). The heterogeneity index alpha of human high-grade gliomas is significantly different from those of normal brain structures, which potentially offers a new method for evaluating brain tumors. The observed negative correlation between tumor alpha and tumor DDC requires further investigation.