Single Pair Arterial Spin Labeling Imaging

Introduction Arterial spin labelling (ASL) is a powerful non-invasive MR technique to examine cerebral blood flow (CBF), in which the perfusion weighted signal comes from the difference between a flow sensitive (label) image and non-sensitive (control) image. Due to the small amplitude of this difference, a large number of such pairs have to be acquired to derive a sufficient level of Contrast to Noise Ratio (CNR) based on signal averaging. This results in prolonged experimental duration making data susceptible to physiological noise and importantly for clinical applications may proves to be unfeasible in challenging patients such those with as Alzheimer's and Parkinson’s diseases. Recently efforts have been made to accelerate perfusion acquisition [1]. Two major sources of signal loss are T1 relaxation of tagged magnetization during transit between the labelling zone and imaging slice and T2* relaxation during imaging readout. In multislice acquisitions the labelling zone can be a significant distance from central slices within the imaging pack. Single slice imaging with a tightly restricted inversion slab reduces the dead zone between imaging slice and tagging zone and may reduce the tagged signal lose due to transit delay. In this work, we present a FAIR [2] based technique to accelerate perfusion image acquisition through a combination of single slice imaging and spiral readout to mininize TE.