Comparison of different simulation approaches to predict signal evolutions and quantitative values in diffusion-sensitized MR Fingerprinting

Motivation: For quantitative methods like MRF an accurate yet fast simulation of signal evolutions is essential. For fast simulations, ignoring time-evolutions of RF-pulses or actual diffusion directions are common practice even though these can affect the resulting fingerprints. Goal(s): We investigate some of these simplifications and their influence on the resulting signal evolutions and quantitative values. Approach: For this we simulate and analyze some possible impacts separately and compare the resulting signal evolutions and quantitative values. Results: In conclusion, while ignoring diffusion directions has negligible impact on the results, assuming instantaneous RF-pulses or ignoring B1-field variances leads to significant differences in the results. Impact: Simplifications like ignoring B1-inhomogeneities, slice profile or time-evolution of RF-pulses lead to significant differences in simulated fingerprints. On the other hand, ignoring the diffusion directions in case of Gaussian diffusion has negligible influence on the signal evolution and quantitative values.