[CT and MRI of the central nervous system: current concepts]

The advents of multidetector-row CT and high-field MRI have accelerated the technical advancement of the stroke CT and MRI. A novel technique combining volume helical scan and three-dimensional denoising filter can improve conspicuity of the early CT signs by increasing the signal-to-noise ratio and reducing bone-related artifacts. High-filed MRI allows us to use new techniques, such as the susceptibility-weighted imaging, myelin-density imaging, volume diffusion imaging, and neuromelanin imaging. Standardization techniques for the stroke CT and MRI introduced by ASIST-Japan can reduce inter-institutional and intervendor differences, and helps in facilitating multicenter trials concerning acute stroke management.