MRI Contrast Enhancement Of Magnetization Prepared Steady State Sequence: An Optimal Control Framework
Résumé
The present work investigates the possibilities of enhancing MRI contrast between two target tissues in a threedimensional Magnetization-Prepared Rapid Gradient-Echo (MP-RAGE) based on relaxation time's differences. The benefit lies in the adaptation of the GRAPE algorithm to the optimization of a magnetization preparation in a cyclic sequence without full recovery between each cycle. This numerical approach allows optimizing a magnetization preparation of an arbitrary number of radio frequency pulses to enhance contrast, taking in account the establishment of a steady state in the longitudinal component of the magnetization. In vivo validation on rat brain is performed at 11.7T and shows the benefit of an optimized T2Prep-IR compared to a simple inversion to enhance contrast between white and gray matter.
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