David D. Shin1, Thomas T. Liu1, Richard B. Buxton1, Guo Jia2, David J. Dubowitz1
1Center for Functional MRI, University of California, San Diego, La Jolla, CA, United States; 2Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
A novel approach to TRUST (T2 relaxation under spin tagging) for measuring venous O2 saturation (Yv) is presented. Critical to the measurement of Yv is a calibration between R2v and Yv. Although several authors have published calibration data, this are critically technique dependent which limits its universal applicability. We present a theoretical framework and propose a method to measure a R2 difference between two vessels (deltaR2) which removes some of the potential systematic errors from a calibration that is not locally applicable. This reduces the number of fit parameters from 6 to only 3. Initial tests in vivo reveal a better estimate of Yv and OEF than those obtained by assuming universal applicability of all 6 fit parameters. An novel imaging technique (SAVANT) is presented that directly measured the required deltaR2 by Simultaneous Arterial and Venous AcquisitioN of T2
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