Advantages of high b-value diffusion-weighted imaging for preoperative differential diagnosis between embryonal and ependymal tumors at 3 T MRI.

•All embryonal tumors was high-intense on DWI at both b-1000 and b-4000.•Large part of ependymal tumors showed low- or isointensity on DWI at both b-1000 and b-4000.•Minimum ADC values were significantly lower in embryonal tumors than in ependymomas.•The ADC values from high (b-4000) b-value were better for distinguishing embryonal from ependymal tumors.•Stronger negative correlation between cell density and minimum ADC values at b-4000.