FIG. 4.
Comparison of relative error in R2* measurements (i.e., accuracy) for 3 signal models by varying UTE-A acquisition parameters as a function of SNR (top row), ∆TE (middle row), and TEmax (bottom row). SNR was held at 50 for varying ∆TE and TEmax. Noise subtraction and quadratic models showed high accuracy for varying acquisition parameters, except for high R2* values obtained for the longest ∆TE of 1.8 ms. The constant offset model overestimated R2* for the lowest SNR and for high R2* values obtained using longer ∆TEs (≥1ms), and R2* results were dependent on TEmax.