MyJournals Home  

RSS FeedsVolumetric BOLD fMRI simulation: from neurovascular coupling to multivoxel imaging (BMC Medical Imaging)


23 april 2012 21:16:10

Volumetric BOLD fMRI simulation: from neurovascular coupling to multivoxel imaging (BMC Medical Imaging)

Background: The blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) modality has been numerically simulated by calculating single voxel signals. However, the observation on single voxel signals cannot provide information regarding the spatial distribution of the signals. Specifically, a single BOLD voxel signal simulation cannot answer the fundamental question: is the magnetic resonance (MR) image a replica of its underling magnetic susceptibility source? In this paper, we address this problem by proposing a multivoxel volumetric BOLD fMRI simulation model and a susceptibility expression formula for linear neurovascular coupling process, that allow us to examine the BOLD fMRI procedure from neurovascular coupling to MR image formation. Methods: Since MRI technology only senses the magnetism property, we represent a linear neurovascular-coupled BOLD state by a magnetic susceptibility expression formula, which accounts for the parameters of cortical vasculature, intravascular blood oxygenation level, and local neuroactivity. Upon the susceptibility expression of a BOLD state, we carry out volumetric BOLD fMRI simulation by calculating the fieldmap (established by susceptibility magnetization) and the complex multivoxel MR image (by intravoxel dephasing). Given the predefined susceptibility source and the calculated complex MR image, we compare the MR magnitude (phase, respectively) image with the predefined susceptibility source (the calculated fieldmap) by spatial correlation. Results: The spatial correlation between the MR magnitude image and the magnetic susceptibility source is about 0.90 for the settings of TE = 30 ms, B0 = 3 T, voxel size = 100micron, vessel radius = 3micron, and blood volume fraction = 2%. Using these parameters value, the spatial correlation between the MR phase image and the susceptibility-induced fieldmap is close to 1.00. Conclusion: Our simulation results show that the MR magnitude image is not an exact replica of the magnetic susceptibility source (spatial correlation [almost equal to] 0.90), and that the MR phase image conforms closely with the susceptibility-induced fieldmap (spatial correlation [almost equal to] 1.00). Digg Facebook Google StumbleUpon Twitter
370 viewsCategory: Medicine
An evolving perspective on physical activity counselling by medical professionals (BMC Family Practice)
Implementation and Acceptability of Mindful Awareness in Body-Oriented Therapy in Women`s Substance Use Disorder Treatment (Journal of Alternative and Complementary Medicine)
blog comments powered by Disqus
The latest issues of all your favorite science journals on one page


Register | Retrieve



Use these buttons to bookmark us: Digg Facebook Google StumbleUpon Twitter

Valid HTML 4.01 Transitional
Copyright © 2008 - 2018 Indigonet Services B.V.. Contact: Tim Hulsen. Read here our privacy notice.
Other websites of Indigonet Services B.V.: Nieuws Vacatures News Tweets Travel Photos Nachrichten Indigonet Finances Leer Mandarijn