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Abstract #2782

Drift in the Magnetization Transfer Signal: Effect on Quantitative MT Experiments

Ives R. Levesque1, Nikola Stikov2, G. Bruce Pike2, John M. Pauly1

1Electrical Engineering, Stanford University, Stanford, CA, United States; 2Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada

Drift in the signal of MT-weighted short-TR GRE sequences has been observed in quantitative MT experiments at two different sites. Signal decreases of 2-6% were observed over the course of data acquisitions in phantoms and in vivo. Drift appears to depend on the duration of the acquisition and on the MT pulse characteristics. The drift likely affects QMTI parameter estimates, in a manner dependent on the experimental method. We present our investigation into this effect, and discuss potential causes including B1 drift related to RF amplifier and/or coil performance, and temperature-related T1 increases.