Michael Malmberg1, Dennis L Parker2, and Henrik L Odéen2
1Biomedical Engineering, University of Utah, Salt Lake City, UT, United States, 2Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States
1Biomedical Engineering, University of Utah, Salt Lake City, UT, United States, 2Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States
Neglecting T2* changes in the single reference variable flip angle (SR-VFA) method for T1-mapping produces a systematic bias on T1. This bias can be corrected by measuring T2* changes dynamically, at the expense of noise, which noise could be mitigated through weighted T1-map combinations.
Figure
2: T1
calculation bias for standard VFA method, SR-VFA method, and T2*
corrected SR-VFA method. TR = 10 ms, T1 baseline = 350 ms, TE/T2*
= 0.2;. SR-VFA line is equivalent with the bolded lines in Figure 1.
Figure 1: (left)
– T1 calculation bias vs Z ratio with TE/T2* = 0.2; (right)
– T1 calculation bias vs TE/T2* with Z ratio = 0.5; For both plots – TR = 10 ms, T1
baseline = 350 ms, α = 6.4°, β = 21.2°. Bolded
lines are equivalent.