Improved ASL Contrast in Multiphase STAR Labeling

F. F. Paiva¹, B. U. Foerster², F. Tovar-Moll¹, J. Moll¹

Multiphase ASL is an effective way to overcome the regional variation of the transit time that difficult the estimation of perfusion values. However, with conventional multiple phases ASL techniques, the ASL contrast at later phases is impaired due to repeated application of excitation pulses and longitudinal relaxation making it difficult to evaluate the tissue perfusion in regions where the transit time is longer. In the present study, we present an improvement of the acquisition scheme by exploring a modulation on the flip angle of the MR acquisition to keep the ASL contrast constant over multiple phases.