Analytical Method for Correction of B1 Errors in High-Field Magnetization Transfer Ratio Mapping

Vasily L. Yarnykh¹

Magnetization Transfer Ratio (MTR) is known to strongly vary with B1. This circumstance restricts MTR applications in high magnetic fields. In this study, a simple analytical model of MTR dependence on B1 was derived. Based on this model, a correction algorithm employing a tissue-independent set of parameters was developed and tested for MTR mapping of the human brain at 3T. MTR correction was shown to be highly accurate across a wide range of B1 non-uniformities. Combination of this algorithm with fast B1 mapping enables whole-brain MTR mapping and histogram analysis on high-field scanners for a variety of neuroimaging applications.