Isotropic diffusion-weighted and spiral-navigated interleaved EPI for routine imaging of acute stroke

Magn Reson Med. 1997 Nov;38(5):741-9. doi: 10.1002/mrm.1910380510.


An interleaved echo-planar imaging (EPI) technique is presented for the rapid acquisition of isotropic diffusion-weighted images of stroke patients. Sixteen isotropic diffusion-weighted images at three b values are acquired in less than 3 min. A spiral navigator echo is used to measure the constant and linear phase shifts across the head in both the x and y directions which result from motion during the isotropic diffusion- sensitizing gradients. The measured k-space errors are corrected during a gridding reconstruction. The gridding kernel has a constant width in kx and a variable width in ky which eliminates variable data-density ghosts. The resulting isotropic diffusion-weighted images have excellent lesion-to-normal brain contrast, very good spatial resolution, and little sensitivity to susceptibility effects in the base of the brain. Examples of diffusion-weighted images and ADC maps from several stroke patients are shown.

MeSH terms

  • Acute Disease
  • Artifacts
  • Brain / pathology*
  • Cerebrovascular Disorders / diagnosis*
  • Echo-Planar Imaging / methods*
  • Humans
  • Image Processing, Computer-Assisted
  • Time Factors