Kelvin Chow1, Jacqueline A. Flewitt2, Joseph J. Pagano1, Jordin D. Green3, Matthias G. Friedrich2, Richard B. Thompson1
1Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada; 2Stephenson CMR Centre, University of Calgary, Calgary, Alberta, Canada; 3Siemens Healthcare, Calgary, Alberta, Canada
The MOLLI T1 mapping sequence was modeled using simulations, its accuracy investigated in phantoms and in-vivo studies, and compared to a new SAturation-recovery single-SHot Acquisition "SASHA" technique. Bloch equation simulations of MOLLI predict systematic T1 underestimation with shorter T2s and also with imperfect inversion pulse efficiency. Measured MOLLI T1s in phantoms agree well with simulations (10% underestimation of myocardium-like phantoms). Incorporating actual inversion pulse efficiency (measured in-vivo at 91%) and T2s into simulations accurately predict observed ~200ms T1 underestimation by MOLLI compared to SASHA in the myocardium. SASHA had good agreement with gold-standard T1s and showed no T2 dependence.