Abstract #1635

Dependence of BOLD Signal Amplitude on Baseline Venous Oxygenation and Cerebral Blood Flow

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.