Improved quantitative myocardial T2 mapping: impact of the fitting model

Purpose: To develop an improved T2 prepared (T2prep) balanced steady-state free-precession (bSSFP) sequence and signal relaxation curve fitting method for myocardial T2 mapping. Methods: Myocardial T2 mapping is commonly performed by acquisition of multiple T2prep bSSFP images and estimating the vox...

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Main Authors: Akçakaya, Mehmet (Author) , Weingärtner, Sebastian (Author)
Format: Article (Journal)
Language:English
Published: 7 August 2014
In: Magnetic resonance in medicine
Year: 2014, Volume: 74, Issue: 1, Pages: 93-105
ISSN:1522-2594
DOI:10.1002/mrm.25377
Online Access:Verlag, Volltext: http://dx.doi.org/10.1002/mrm.25377
Verlag, Volltext: http://onlinelibrary.wiley.com.ezproxy.medma.uni-heidelberg.de/doi/10.1002/mrm.25377/abstract
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Author Notes:Mehmet Akçakaya, Tamer A. Basha, Sebastian Weingärtner, Sébastien Roujol, Sophie Berg, and Reza Nezafat
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Summary:Purpose: To develop an improved T2 prepared (T2prep) balanced steady-state free-precession (bSSFP) sequence and signal relaxation curve fitting method for myocardial T2 mapping. Methods: Myocardial T2 mapping is commonly performed by acquisition of multiple T2prep bSSFP images and estimating the voxel-wise T2 values using a two-parameter fit for relaxation. However, a two-parameter fit model does not take into account the effect of imaging pulses in a bSSFP sequence or other imperfections in T2prep RF pulses, which may decrease the robustness of T2 mapping. Therefore, we propose a novel T2 mapping sequence that incorporates an additional image acquired with saturation preparation, simulating a very long T2prep echo time. This enables the robust estimation of T2 maps using a 3-parameter fit model, which captures the effect of imaging pulses and other imperfections. Phantom imaging is performed to compare the T2 maps generated using the proposed 3-parameter model with the conventional two-parameter model, as well as a spin echo reference. In vivo imaging is performed on eight healthy subjects to compare the different fitting models. Results: Phantom and in vivo data show that the T2 values generated by the proposed 3-parameter model fitting do not change with different choices of the T2prep echo times, and are not statistically different than the reference values for the phantom (P = 0.10 with three T2prep echoes). The two-parameter model exhibits dependence on the choice of T2prep echo times and are significantly different than the reference values (P = 0.01 with three T2prep echoes). Conclusion: The proposed imaging sequence in combination with a three-parameter model allows accurate measurement of myocardial T2 values, which is independent of number and duration of T2prep echo times.
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Physical Description:Online Resource
ISSN:1522-2594
DOI:10.1002/mrm.25377