Optimisation of quantitative Magnetisation Transfer (qMT) sequence acquisition parameters
Symms M, Cercignani M, Tozer D, Samson R, Tofts P
Institute of Neurology
We optimise quantitative Magnetisation Transfer (qMT) acquisition to minimise uncertainty of parameter estimates, using the Cramer-Rao Minimum Variance Bound (CRMVB). Acquisition was optimised theoretically to estimate f/RA(1-f), a measure of the fraction of protons that are bound to macromolecules, or T2B, their T2 value, or both (with remaining parameters fixed). For estimation of both parameters, a 39% reduction in the standard deviation (SD) of T2B estimates and a 17% reduction in the f/RA(1-f) SD were observed experimentally compared to an existing acquisition scheme, verifying theoretical calculations and numerical simulations. Alternatively, qMT acquisition time could be reduced using this approach.