Arterial spin labeling (ASL)
- ASL uses an endogenous flow tracer analogous to O-15 water and can yield a quantitative measure of cerebral blood flow.
- Developments over the past decade now permit efficient, noninvasive whole brain imaging, appropriate for use in studies of development.
- Resting perfusion fMRI studies may offer a useful alternative or adjunct to BOLD fMRI studies. Resting perfusion may be correlated with diagnosis or behavioral measures obtained outside the scanner.
- Activation signals in ASL come primarily from the microvasculature (capillaries), as in PET.
- ASL may offer greater stability for developmental studies and studies of phenomena that cannot be easily turned on and off, (e.g., mood states, learning, and pharmacological effects).
- ASL may have potential as a biomarker for abnormal brain function due to its stability.