How reliable is PW-MRI to detect elevated oxygen extraction fraciton (OEF-PET) in stroke?

Background: The accuracy of perfusion weighted MRI based quantitative maps of relative CBF, relative CBV, relative MTT and relative TTP remains a matter of debate. We validated PWI-maps on OEF measurement by quantitative 15O-water-PET with respect to the detection of elevated OEF (penumbra). Methods: PW-MRI was performed on a 1.5 Tesla scanner (Philips) using a 3D EPI-PRESTO sequence; OEF-PET was performed on an ECAT EXACT HR scanner (Siemens/CTI). In acute and subacute stroke patients, the rCBF-, rCBV-, rMTT- and rTTP-PWI and OEF-PET maps were compared. ROI's were placed over the cortex of the affected hemisphe…