On the accuracy and precision of cardiac magnetic resonance T2 mapping: A high‐resolution radial study using adiabatic T2 preparation at 3 T

Purpose The goal of this study was to characterize the accuracy and precision of cardiac T 2 mapping as a function of different factors including low signal‐to‐noise ratio (SNR), imaging in systole, and off‐resonance frequencies. Methods Bloch equation and Monte Carlo simulations were used to determine the influence of SNR and the choice of T 2 preparation echo time (TE T2prep ) increments on the accuracy and precision of high‐resolution radial cardiac T 2 mapping at 3.0 T. Healthy volunteers were scanned to establish the difference in precision and inter‐ and intraobserver variability between T 2 mapping in diastole and systole, as well as the effect of SNR and off‐resonance frequencies on the accuracy of T 2 maps. Results The simulations demonstrated that a TE T2prep increment of ∼0.75 times the T 2 value of interest optimally increases the precision of the T 2 fit. Systolic T 2 maps were found to have a higher precision ( P = 0.002), but similar inter‐ and intraobserver variability compared with diastolic T 2 maps, whereas off‐resonance frequencies beyond ± 100 Hz cause a significant decrease in both accuracy and precision ( P < 0.05). Conclusion This evaluation of the accuracy and precision of cardiac T 2 mapping characterizes the major vulnerabilities of the technique and will help guide protocol definition of studies that include T 2 mapping. Magn Reson Med 77:159–169, 2017. © 2016 Wiley Periodicals, Inc.