Correction for the echo-shifting related artifacts in T2* mapping
Chen N, Chou Y, Panych L, Oshio K
Brigham and Women's Hospital, Harvard Medical School
T2* mapping is a commonly performed MRI procedure, and is useful for characterizing tissue properties. However, our analysis and experimental data show that, in the presence of background susceptibility field gradients (e.g. near the air-tissue interface), the echo-shifting effect and TE-shifting effect will make the calculated T2* maps inaccurate. We further demonstrate that accurate T2* mapping can only be achieved after (1) quantifying the echo-shifting effect (in gradient-echo EPI and gradient-echo imaging) with the k-space energy spectrum analysis algorithm, and (2) correcting for the TE-shifting effect in T2* calculation.