Simultaneous multislice triple-echo steady-state (SMS-TESS): T1, T2, PD, and off-resonance mapping in the human brain

Purpose : To investigate the ability of simultaneous multislice triple-echo steady-state (SMS- TESS) imaging to provide quantitative maps of multiple tissue parameters, i.e., longitudinal and transverse relaxation times (T 1 and T 2 ), proton density (PD), and off-resonance ( ∆ B 0 ), in the human brain at 3 T from a single scan. Methods : TESS acquisitions were performed in 2D mode to reduce motion sensitivity and accelerated by a simultaneous multislice excitation scheme (CAIPIRINHA) with SENSE reconstruction. SMS-acceleration factors (R) of 2 and 4 were evaluated. The in vitro and in vivo validation process included standard reference scans to analyze the accuracy of T 1 , T 2 , and  B 0 estimates, as well as single-slice TESS measurements. Results : For R=2, the quantification of T 1 , T 2 , PD, and ∆ B 0 was overall reliable with marginal noise enhancement. T 1 and T 2 values were in good agreement with the reference measurements and single-slice TESS. For R=4, the agreement of  B 0 with the standard reference was excellent and the determination of T 1 , T 2 , and PD was reproducible, however, increased variations in T 1 and T 2 values with respect to single-slice TESS were observed. Conclusion : SMS-TESS has shown potential to offer rapid simultaneous T 1 , T 2 , PD, and ∆ B 0 mapping of human brain tissues.