Characterization and correction for Modified Look Locker (MOLLI) T1 mapping using Bloch simulations and corroboration with scan measurements

Wednesday, October 26, 2011 — Poster Session III
10:00 a.m. – Noon	Natcher Conference Center	CC	IMAG-9

Authors

• N Gai
• C Stehning
• M Nacif
• D Bluemke

Abstract

Recently, it has been shown that T1 mapping MRI can differentiate between diffuse fibrosis and normal myocardium. MOLLI is the current state-of-the-art T1 mapping technique in cardiac MRI. MOLLI is more robust to cardiac motion as data are acquired in the same quiescent window of several cardiac cycles. Subsequent work in literature related to optimization of parameters to improve accuracy of calculated T1 values was purely experimental based on performing phantom scans while varying scan parameters. In addition to being time consuming, such an approach fails to be comprehensive in the covered parameter space as well as the parameters thought to influence T1 values. For example, the effect of T2 on T1 accuracy was not explored. In this work, we develop a Bloch simulation based characterization of the MOLLI sequence and evaluate T1 accuracy for several different scan parameters. We corroborate T1 values obtained from simulation with values obtained from scanning phantoms and normal volunteers and show excellent correspondence. Based on simulations and scanning results, we show that the simulation is a valuable tool in understanding the accuracy of MOLLI derived T1 values and can be used to correct for inaccuracies resulting from differences in implementation across scanners and subjects.

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