The search functionality is under construction.

IEICE TRANSACTIONS on Information

An Explanation of Signal Changes in DW-fMRI: Monte Carlo Simulation Study of Restricted Diffusion of Water Molecules Using 3D and Two-Compartment Cortical Cell Models

Shizue NAGAHARA, Takenori OIDA, Tetsuo KOBAYASHI

  • Full Text Views

    0

  • Cite this

Summary :

Diffusion-weighted (DW)-functional magnetic resonance imaging (fMRI) is a recently reported technique for measuring neural activities by using diffusion-weighted imaging (DWI). DW-fMRI is based on the property that cortical cells swell when the brain is activated. This approach can be used to observe changes in water diffusion around cortical cells. The spatial and temporal resolutions of DW-fMRI are superior to those of blood-oxygenation-level-dependent (BOLD)-fMRI. To investigate how the DWI signal intensities change in DW-fMRI measurement, we carried out Monte Carlo simulations to evaluate the intensities before and after cell swelling. In the simulations, we modeled cortical cells as two compartments by considering differences between the intracellular and the extracellular regions. Simulation results suggested that DWI signal intensities increase after cell swelling because of an increase in the intracellular volume ratio. The simulation model with two compartments, which respectively represent the intracellular and the extracellular regions, shows that the differences in the DWI signal intensities depend on the ratio of the intracellular and the extracellular volumes. We also investigated the MPG parameters, b-value, and separation time dependences on the percent signal changes in DW-fMRI and obtained useful results for DW-fMRI measurements.

Publication
IEICE TRANSACTIONS on Information Vol.E96-D No.6 pp.1387-1393
Publication Date
2013/06/01
Publicized
Online ISSN
1745-1361
DOI
10.1587/transinf.E96.D.1387
Type of Manuscript
PAPER
Category
Biological Engineering

Authors

Shizue NAGAHARA
  Kyoto University,Japan Society for the Promotion of Science
Takenori OIDA
  Kyoto University
Tetsuo KOBAYASHI
  Kyoto University

Keyword