Introduction: In acute ischemic stroke, perfusion imaging facilitates detection of the occluded vessels, influences decision-making regarding therapy options, and is recommended especially in delayed time windows. In contrast to conventional CT perfusion (CTP), flat panel detector CT perfusion (FD-CTP) can be acquired directly in the angio suite. To evaluate FD-CTP imaging, we assessed clinically important qualitative and quantitative perfusion parameters in correlation to prior acquired conventional CTP using the new RAPID for Angio software. Methods: We included patients with ICA-, M1, or M2-occlusions from 6 centers. All patients underwent mechanical thrombectomy (MT) with pre-interventional conventional CTP and FD-CTP imaging. Quantitative performance was determined by comparing volumes of infarct core, penumbral tissue, and mismatch volume. Eligibility for MT according to the perfusion imaging criteria of DEFUSE 3 was determined for each case for conventional CTP and FD-CTP imaging. A blinded reader identified the occlusion site based on visual inspection of the FD-CTP maps. Results: We included 77 patients and FD-CTP was technical adequate in 49 patients (63.6%). The final analysis included 20 patients (further reasons for exclusion were n=20 technical inadequate conventional CTP, n=2 reperfusion between scans, n=2 exceeding the time limit between scans, n=2 posterior occlusion and n=3 MRI-perfusion). Conventional rCBF <30% and FD-CTP rCBF <45% showed good correlation (R ² = 0.84). Conventional CTP Tmax >6s/FD-CTP Tmax >6s and CTP Mismatch/FD-CTP Mismatch showed more variability (R ² = 0.57, and R ² = 0.33 respectively). Based on FD-CTP, 16/20 (80%) patients met the inclusion criteria for MT according to the DEFUSE 3 perfusion criteria in contrast to 18/20 (90%) patients based on conventional CTP. A blinded reader correctly determined the specific vessel occlusions in 34/38 cases (89.5%). Conclusion: In our multicenter study, time-resolved whole-brain FD-CTP was technically feasible and qualitative and quantitative perfusion results correlated overall well with conventional CTP. This potentially enables a direct to the angio approach to be established and may increase the chances of good clinical outcome.