Neuroscience 2005 Abstract
| Presentation Number: | 10.12 |
|---|---|
| Abstract Title: | Application of vascular masks to functional MRI signals. |
| Authors: |
Chavez, A. A.*1
; Wu, W.1
; Yoder, E. J.1
1Radiology, UCSD Ctr. for fMRI, La Jolla, CA |
| Primary Theme and Topics |
Homeostatic and Neuroendocrine Systems - Brain Blood Flow, Metabolism and Homeostasis -- Functional imaging |
| Secondary Theme and Topics | Homeostatic and Neuroendocrine Systems<br />- Brain Blood Flow, Metabolism and Homeostasis<br />-- Blood flow |
| Session: |
10. Energy Metabolism and Blood Flow Slide |
| Presentation Time: | Saturday, November 12, 2005 3:45 PM-4:00 PM |
| Location: | Washington Convention Center - Room 140A |
| Keywords: |
BOLD fMRI is often used to map the locations of brain activity. Analysis of BOLD data typically identifies volumes of activation by mapping where BOLD signals are temporally correlated to task performance. This procedure does not distinguish between volumes located near the origin of activation and those in remote veins and sinuses. In order to separate BOLD signals in large veins and sinuses from signals in the parenchyma, we collected images of the brain’s venous system and used these to create vascular masks. Functional and vascular data sets were co-registered, and the skull was extracted from the images. BOLD signal correlations to a reference function were calculated for each voxel, and voxels with a correlation coefficient of 0.6 or greater were used to create an activation mask. A vascular mask was created from the 2.8% most intense brain voxels in the venogram, which approximates the amount of venous cerebral blood volume. This voxel-selection method is independent of the absolute intensity values, which may vary with fluctuations in scanner gain. The vascular mask was resampled to match the spatial resolution of the functional data, and an inverse mask was created for nonvessel regions. Average time courses were generated for voxels contained in both the vessel and nonvessel and activation masks. Initial results suggest that response amplitude was higher for vessel-based signals than non vessel-based signals. Furthermore, the BOLD signal undershoot was more pronounced for vessel-based than nonvessel-based voxels. Thus, vascular masks may be used to filter “downstream” vascular signals from BOLD fMRI data in order to more precisely map, characterize, and quantify brain activations.
Supported by NIH (EB003436)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
Copyright © 2005-2026 Society for Neuroscience; all rights reserved. Permission to republish any abstract or part of any abstract in any form must be obtained in writing by SfN office prior to publication.
