Segmentation analysis in functional MRI: activation sensitivity and gray-matter specificity of RARE and FLASH.


Journal Article

Brain activation is accompanied by local decreases in vascular deoxyhemoglobin. Theoretically, gradient-echo and spin-echo sequences show similar sensitivity to capillary deoxyhemoglobin, but spin-echo sequences should be less sensitive to venous deoxyhemoglobin. This is an important distinction in the context of cortical localization. We report herein a direct experimental comparison of a gradient-echo sequence (fast low-angle shot [FLASH]) with a spin-echo sequence (rapid acquisition with relaxation enhancement [RARE]) for functional MRI (fMRI) in seven subjects undergoing visual stimulation. A Student t test analysis was used to locate areas of significant activation, and then computerized image segmentation was performed to determine the type of activated tissue. Contrary to previous reports, both sequences proved equally sensitive to overall activation. RARE activation, however, was more specific for gray matter, as suggested by prior theoretical models.

Full Text

Cited Authors

  • Hutchinson, M; Rusinek, H; Nenov, VI; Feinberg, DA; Johnson, G

Published Date

  • March 1997

Published In

Volume / Issue

  • 7 / 2

Start / End Page

  • 361 - 364

PubMed ID

  • 9090591

Pubmed Central ID

  • 9090591

Electronic International Standard Serial Number (EISSN)

  • 1522-2586

International Standard Serial Number (ISSN)

  • 1053-1807

Digital Object Identifier (DOI)

  • 10.1002/jmri.1880070217


  • eng