The effect of off-resonance radiofrequency pulse saturation on fMRI contrast.


Journal Article

This paper describes the use of off-resonance saturation to further manipulate the blood oxygenation level dependent (BOLD) contrast of fMRI. A customized narrow bandwidth radiofrequency pulse, applied with a range of frequency offsets prior to selection of each slice, was designed and incorporated into a gradient echo EPI sequence. This application takes advantage of the resonance frequency and linewidth differences between the oxygenated and deoxygenated state of blood in human brain during task activation and rest, and is capable of creating an enhancement in the contrast of the BOLD effect. Because of a possible contribution to the signal change from cerebro-spinal fluid, which has a much narrower linewidth and smaller frequency shift compared with the brain tissue, data were also collected using a nulling inversion pulse. The inversion pulse was applied before the off-resonance pulse and data acquisition to eliminate the CSF signal. Functional areas are thus more localized to the brain tissue.

Full Text

Duke Authors

Cited Authors

  • Song, AW; Wolff, SD; Balaban, RS; Jezzard, P

Published Date

  • June 1997

Published In

Volume / Issue

  • 10 / 4-5

Start / End Page

  • 208 - 215

PubMed ID

  • 9430350

Pubmed Central ID

  • 9430350

International Standard Serial Number (ISSN)

  • 0952-3480

Digital Object Identifier (DOI)

  • 10.1002/(sici)1099-1492(199706/08)10:4/5<208::aid-nbm467>;2-s


  • eng

Conference Location

  • England