Enhanced spatial localization of neuronal activation using simultaneous apparent-diffusion-coefficient and blood-oxygenation functional magnetic resonance imaging.

Published

Journal Article

Functional MRI (fMRI) can detect blood oxygenation level dependent (BOLD) hemodynamic responses secondary to local neuronal activity. The most commonly used method for detecting fMRI signals is the gradient-echo echo-planar imaging (EPI) technique because of its sensitivity and speed. However, it is known that much of the signal obtained with this approach arises from large veins, with additional contribution from the capillaries and venules. Early experiments using diffusion-weighted gradient-echo EPI have suggested that intravoxel incoherent motion (IVIM) weighting can selectively attenuate contributions from large vessels based on the differences in the mobility of the blood within them, thereby revealing the contributions from hemodynamic changes in capillaries, which are in close spatial proximity to the activated neural tissue. Using this differential sensitivity of the various neurovascular compartments to IVIM weighting, we present a new approach for deriving functional maps of neural activity. This method is based on task-induced changes of the apparent diffusion coefficients (ADC), a signal that we demonstrate is generated in vascular compartments that only partially overlap with those generating the BOLD signal. The approach allows both the ADC-based maps and the more commonly used BOLD-based maps to be acquired simultaneously. The spatial overlap between these maps can be used to create composite maps that permit improved localization of the underlying neuronal activity patterns by identifying signals generated in those vascular components that are in closest proximity to the active neuronal populations of interest.

Full Text

Duke Authors

Cited Authors

  • Song, AW; Woldorff, MG; Gangstead, S; Mangun, GR; McCarthy, G

Published Date

  • October 2002

Published In

Volume / Issue

  • 17 / 2

Start / End Page

  • 742 - 750

PubMed ID

  • 12377149

Pubmed Central ID

  • 12377149

International Standard Serial Number (ISSN)

  • 1053-8119

Language

  • eng

Conference Location

  • United States