Talks and Conference Presentations
International Society for Magnetic Resonance in Medicine
12th Scientific Meeting & Exhibition
May 15-21, 2004
Compartmental Selectivity of Diffusion Weighted BOLD fMRI at 4T
Charles R. Michelich, Allen W. Song, James R. MacFall
Conventional blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) techniques provide a non-invasive tool to monitor brain activity through the vascular response to changes in neuronal activity. While this technique provides a valuable tool to clinicians and researchers, contributions from large vessels distant from the site of neuronal activity limit the specificity of conventional gradient-echo BOLD imaging. A number of approaches have been introduced to reduce the contribution of large vessels in BOLD fMRI. Low levels of diffusion weighting have been used to suppress intravascular contributions to BOLD contrast. Spin-echo acquisition has been used to selectively suppress the BOLD signal from the area surrounding large vessels. Imaging at higher field strengths can also help to suppress vascular contributions due to the shortened T2* of blood. The goal of this research was to systematically investigate the combined effect of these approaches to BOLD small vessel localization through an analysis of compartmental selectivity for the purposes of protocol design and development of new functional imaging methods.