Adaptive Averaging Improves the Signal to Noise Ration in ASL Experiments Especially at High Inflow Times

Johanna Kramme¹, Johannes Gregori¹, Matthias Gnther^1,2

A challenge in Arterial Spin Labeling experiments is low Signal to Noise Ratio (SNR) and physiological noise, especially at inflow times above 2500ms. For time series over 3000ms a high number of averages was necessary to guaranty sufficient SNR, leading to long scan times. In this work a 3D-GRASE sequence is presented which is capable of adaptive averaging, allowing to average higher TIs more often than lower ones. Due to this scan times can be halved, by increasing the SNR by at least one halve compared to standard imaging where all inflow times are imaged equal number of times.