Acquisition Aspects of Functional and Clinical Arterial Spin Labeling

Arterial spin labeling (ASL) enables noninvasive, quantitative MRI measurements of tissue perfusion and has a broad range of applications including functional brain imaging. ASL can concurrently measure perfusion and blood oxygenation-level-dependent (BOLD) signal changes, which proves useful for investigating the brain’s physiology in health and disease. However, ASL suffers from limited temporal resolution and has a lower signal-to-noise ratio (SNR) compared to conventional BOLD imaging. Therefore, most of the ASL research to date has focused on improving its SNR and temporal resolution. In this chapter, the functioning, advantages, disadvantages, and application areas of ASL are summarized. Further, the acquisition approaches and imaging parameters that influence ASL’s SNR and temporal resolution are reviewed. Finally, the effects of labeling schemes, background suppression, and readout approaches, as well as the potential of ultrahigh magnetic fields and acceleration techniques, are discussed. The ASL technical developments described here are key to its utilization increase in both neuroscience research and clinical applications.