Summary

In summary, the Bloch-McConnell equations, an analytical solution to the steady-state signal can be derived and fitted with one of the existing models that make different approximations to fit the qMT data for a different set of parameters. The Sled and Pike model Sled & Pike, 2001 constrains the solution space by computing complementary T₁ maps, whose acquisition method influences the B₁ sensitivity of the fitted parameters Boudreau et al., 2018. This fitting model can be implemented with a continuous or a rectangular wave irradiation of the restricted pool Cabana et al., 2015. Ramani’s fitting model is an alternative approach that assumes a continuous wave irradiation scheme with the MT pulse on both free and restricted pools Ramani et al., 2002. Another fitting model was proposed by Yarnykh Yarnykh, 2002 where an analytical solution to describe the magnetization is found when the direct saturation of the free pool is neglected.

In future blog posts, we will explore other MT methods, such as MTR Wolff & Balaban, 1989, MTsat Helms et al., 2008 and qMT-bSSFP Bieri & Scheffler, 2007Gloor et al., 2008. Additionally, we will also be looking at the effects of RF field inhomogeneity on the generated magnetization transfer maps.