Normalized magnitude signal decay curve for IR-UTE images of a cadaveric human bone sample with a TR of 300 ms, a TI of 20 ms and TEs ranging from 8 µs to 5 ms (A), and selected magnitude and corresponding phase images with a TE of 8 us (B, F), 0.4 ms (C, G), 0.6 ms (D, H) and 1.4 ms (E, I). The relative longitudinal magnetizations of bound water (BM) and pore water (FW) at different TEs are also shown in (A), where the positive signal from bound water dominates the IR-UTE signal at short TEs. This signal decays quickly with increasing TEs, leaving the negative signal from pore water which decays more slowly dominating the IR-UTE signal at longer TEs. In subfigures (F) to (I) the signals were of opposite phase before and after TE of 0.5 ms (i.e., ϕ = 0.27 for TE of 8 µs, ϕ = 0.74 for TE of 0.4 ms, while ϕ = −2.47 for TE of 0.6 ms and ϕ = −2.03 for TE of 1.4 ms), consistent with a transition from positive to negative net magnetization at TE ~0.5 ms, the null point.