Insensitive to Off-Resonance 3D T1/T2 Mapping SPGR/bSSFP using Dictionary-Matching: Application to the Prostate at 3T

Balanced Steady State Free Precession (bSSFP) has been successfully used to estimate T2 maps (DESPOT2), but bSSFP is prone to off-resonance artifacts. These artifacts affect the reconstruction of the T2 maps. We propose a dictionary-matching reconstruction using the signal model of bSSFP and spoiled gradient echo (SPGR). We tested this approach with simulation, 3D phantom and 3D in-vivo prostate acquisitions. In all of them, the off-resonance banding artifacts are greatly reduced, which is reflected in reduced NRMSE values. This method allows using a faster sequence with high SNR to quantify complicated body regions like the prostate.