Kay Jann1, Martinus Hauf2, Frauke Kellner-Weldon2, Marwan Mohamed El-Koussy2, Claus Kiefer2, Andrea Federspiel1, Gerhard Schroth2
1Department of Psychiatric Neurophysiology, University Hospital of Psychiatry / University of Bern, Bern, Switzerland; 2University Institute of Diagnostic & Interventional Neuroradiology, Inselspital & University of Bern, Bern, Switzerland
The time needed by labelled blood to reach the cortical capillaries (parenchyma phase) has to be accounted for in ASL, therefore a delay between labelling and readout is introduced. The duration of this delay is limited by the fast T1 relaxation-time to only a few seconds. In patients with steno-occlusive arterial disease (SOAD) above the labelling plane (intracranial stenosis) this time window might be too narrow due to prolonged arrival times to the parenchyma. We estimated to what extent arrival is delayed in patients with SOAD and from which vascular compartment the ASL signal origins at a given delay time.