Positron emission computed tomography (PET) is used for evaluating cerebral hemodynamic ischemic stages in patients with major cerebrovascular stenosis/occlusion for treatment indication. Using a rapid, low-resolution pre-scan method, arterial transit time (ATT) and corrected cerebral blood flow (CBF) could be obtained, even in the immediate clinical setting. This study aimed to clarify whether ATT is hemodynamically related to misery perfusion stratified with 15O-H2O/15O2-gas PET data. There was a significant correlation between ASL and PET CBF before and after ATT correction (r2=0.27, 0.55). ATT also significantly correlated with PET-OEF (r2=0.11) and is a useful parameter to classify cerebral ischemia.