Related Experiment Video
Updated: May 1, 2026
Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats
Published on: July 19, 2013
Instantaneous signal loss simulation (InSiL): an improved algorithm for myocardial T₁ mapping using the MOLLI
Jiaxin Shao1, Kim-Lien Nguyen, Yutaka Natsuaki
1Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
Purpose:
To propose a T1 mapping algorithm for the modified Look-Locker inversion-recovery (MOLLI) sequence that can improve T1 estimation accuracy.
Materials And Methods:
The modified T1 mapping algorithm (InSiL) is based on the simulation of MOLLI signal evolution and simulates the longitudinal magnetization signal perturbation by each single-shot image acquisition in MOLLI as an instantaneous signal loss. InSiL was evaluated against original MOLLI using Bloch simulations, phantom studies, and in 15 healthy volunteers at 1.5T.
Results:
In phantom studies, the maximum absolute error by InSiL is less than 2%, while that by MOLLI is more than 20% for T1 values from 221 msec to 1539 msec. The benefit of InSiL is greatest at heart rate (HR) >80 bpm and T1 >1000 msec, and InSiL reduced MOLLI T1 error from 14.9 ± 4.5% to 0.4 ± 0.3%. Average InSiL-derived native myocardial T1 values at 1.5T in healthy volunteers were significantly higher than MOLLI-derived values by 236.9 ± 11.7 msec (1160.3 ± 25.1 msec vs. 923.4 ± 22.3 msec, P < 0.001) at an average HR of 65.1 ± 14.7 bpm.
Conclusion:
The proposed InSiL approach yields better T1 mapping accuracy than MOLLI, and is less sensitive to HR variation in tissues with longer T1 values.
