Joy Liau1, Youngkyoo Jung2, Anna Leigh Rack-Gomer3, Thomas Liu4
1UC San Diego Center for Functional MRI, La Jolla, CA; 2UCSD Center for fMRI, La Jolla, CA; 3UCSD Center for FMRI, La Jolla, CA; 4UC San Diego Center for Functional MRI, La Jolla, CA, USA
Prior studies have shown a strong correlation across a sample of healthy subjects between the BOLD signal amplitude and measures of baseline venous oxygenation. In addition, a significant correlation has been shown between baseline venous oxygenation and cerebral blood flow (CBF). However, while some studies have found a significant correlation between BOLD signal amplitude and baseline CBF, others have not. In this study we demonstrate that the correlation between BOLD signal amplitude and baseline CBF depends on the gray matter volume fraction of the voxels used to compute the baseline CBF measures.