Figure 2a:

Graphs show simulations of the effect of pore water T2* on porosity index (PI) calculated on the basis of a dual-echo UTE sequence. (a) Association between porosity index and pore water fraction for pore water T2* range of 1–10 msec (ms). (b) Effect of the second TE (ie, long TE) on the dynamic range of porosity index, which shows negligible effect of pore water T2* range of 1–10 msec as long as long TE is greater than 2 msec. The dynamic range was defined as the percent difference in porosity index corresponding to 10% and 50% pore water fraction at each T2* value.