1. BOLD Calibration: Arterial Spin Labeling (ASL) Measurement of CBF

2. Motivation Cerebral Blood Flow (CBF) influences the BOLD Signal Provide a measure of vascular reactivity

3. ASL(Arterial Spin Labeling) Uses RF inversion to “tag” blood and measure where it goes.

4. Proposed Work Plan Year 1: select, implement and test an ASL method Year 2: Parametric assessment of ASL variables Year 3: Develop algorithms for using baseline CBF in BOLD activation calculation Year 4: Validate at sites Year 5: Incorporate into the fBIRN protocol

5. Cocaine Observed brain hypoperfusion after 6 months of abstinence May be to due to impaired cerebral vascular response Measure CBF during a vascular challenge (breathhold) to assess vascular reactivity