(H2O)-O-15 PET validation of steady-state arterial spin tagging cerebral blood flow measurements in humans

Steady-state arterial spin tagging approaches can provide quantitative imag es of CBF, but have not been validated in humans. The work presented here c ompared CBF values measured using steady-state arterial spin tagging with C BF values measured in the same group of human subjects using the (H2O)-O-15 IV bolus PET method. Blood flow values determined by (H2O)-O-15 PET were c orrected for the known effects of incomplete extraction of water across the blood brain barrier. For a cortical strip ROI, blood flow values determine d using arterial spin tagging (64 +/- 12 cc/100g/min) were not statisticall y different from corrected blood flow values determined using (H2O)-O-15 PE T (67 +/- 13 cc/100g/min). However, for a central white matter ROI, blood f low values determined using arterial spin tagging were significantly undere stimated compared to corrected blood flow values determined using (H2O)-O-1 5 PET, This underestimation could be caused by an underestimation of the ar terial transit time for white matter regions. Published 2000 Wiley-Liss, In c.(+).