Comparison between electron density imaging with dual-energy computed tomography without contrast medium and magnetic resonance imaging for high-grade glioma

Dual-energy computed tomography (DECT) has been used for the prediction of glioma grading and malignancy, in addition to magnetic resonance imaging (MRI) findings. In DECT, electron density (ED) can be quantitatively measured and determined with high accuracy. However, no studies have demonstrated whether DECT alone can detect tumor-infiltrating areas or evaluate malignancy. Therefore, we evaluated the use of ED imaging with DECT showing high-density areas of high-grade glioma (HGG), compared it with MRI gadolinium-enhanced T1-weighted image (GdT1) enhancing area, and analyzed its effectiveness in evaluating malignancy. Ten patients with enhanced masses on GdT1 MRI were enrolled in this retrospective study. Ten slices of ED and GdT1 images of 10 patients with HGG were analyzed by three raters. The relationships between the area of high ED on DECT and enhanced area on GdT1 and between the relative ED of the high ED area and contralateral white matter on DECT were determined. Linear regression analysis revealed a positive correlation between areas of high ED and Gd enhancement among all raters (rater A: R2 = 0.910, P < 0.0001, B: R2 = 0.857, P = 0.0001, C: R2 = 0.717, P = 0.002), and the intraclass correlation coefficient was 0.75. A comparison of the relative ED between the tumor and contralateral white matter revealed that the mean and maximum relative ED of the tumor area was significantly higher than that of the contralateral white matter (mean: P = 0.049, maximum: P = 0.0002). ED images of DECT show a high ED area similar to the Gd enhancement area in HGG, and the mean and maximum relative EDs of this area are significantly higher than those of the contralateral white matter.