Abstract #2685

Lee G, Hernandez-Garcia L, Gulani V, Noll D

Previous work in quantifying the perfusion changes during functional experiments using turbo-CASL has assumed a linear relationship between percentage perfusion increase and percentage transit time decrease. The validity of this assumption was explored by measuring CBF and transit time for four different conditions: rest, two levels of motor activation, and rest while breathing 100% oxygen. The relationship of percentage transit time change to percentage flow change was observed to be highly linear (r2>0.9) over the range of perfusions studied. The slope of the relationship was found to be between 0.11 and 0.15 for the subjects scanned.