Fast Whole Brain Quantitative Proton Density Mapping to Normalize 1H MR Spectroscopic Imaging

Angle Lecocq¹, Yann Le Fur², Alexis Amadon³, Alexandre Vignaud³, Monique Bernard⁴, Maxime Guye¹, Jean-Philippe Ranjeva¹

In order to normalize CSI water spectrum to obtain signal normalized MR spectroscopic imaging, absolute ρ-maps have to be computed from T1 and T2* maps accounting for B0 and B1 corrections. In this work, we present a very fast method to generate these ρ-maps. A method called XEP recently proposed to obtain fast B1-maps, was combined with a DESPOT1 sequence, an optimized variable flip angle T1 mapping sequence and a conventional T2* mapping sequence. We first validated this method on phantom, and determined proton density maps in three healthy volunteers also explored by CSI technique.