T1 Effect on BOLD & CBF Functionl Magnetic Resonance Imaging of Hyperoxic Challenge in Ischemic Stroke

Qiang Shen^1,2, Shiliang Huang¹, Fang Du¹, Timothy Q. Duong^1,2

Oxygen challenge (OC) has been used to test vascular function in disease conditions and to estimate ischemic penumbra with T2*-weighted MRI. However, such T2*-weighted signal sources of OC associated with cerebral ischemia remain not well understood. OC is known to cause T1 changes which affect ASL CBF and BOLD signals if TR is insufficiently long. Ischemia also could change T1, CBF, as well the response to OC. The goal of this study was to investigate the T2*-weighted signal sources during OC by measuring T1, T2 and CBF during air and oxygen inhalation associated with ischemic brain injury.