Fast, Accurate and Precise B1 Mapping In vivo using the 180 Null Signal
Dowell N, Tofts P
University College London
RF field B1 nonuniformity is the largest cause of error in the quantitative measurement of clinically-relevant parameters in MR images and spectra. Knowledge of the spatial dependence of B1 will improve the accuracy and precision of such parameters. Here, we present a technique that uses the 180 signal null to construct a B1 map of the entire brain in less than 4 minutes, independent of T1, T2 and PD. The experiment utilizes an existing MR sequence supplied by the scanner manufacturers. Owing to the short scan-time it is envisaged that it may be integrated into existing quantitative MR techniques.