Figure 3

STIR, FLAIR and Black-Blood Preparation schemes. Pulse sequence timing and z-magnetisation curves for the three common special cases of the inversion recovery preparation scheme. In (a) the short TI inversion recovery (STIR) pulse sequence has the TI chosen to correspond to the null point for fat tissue (TI_fat) resulting in the suppression of signal from fat. Note that for a modulus reconstruction, the sign of the magnetisation is ignored and the displayed signal intensity from the other tissues increases with increasing T1 value, with fluid yielding the highest signal intensity. In (b) the fluid attenuated inversion recovery (FLAIR) pulse sequence has the TI chosen to be at the null point for fluid to suppress the signal from fluid (TI_fluid). In (c) the first inversion pulse of the black-blood preparation scheme has its TI chosen to correspond to the null point for blood (TI_blood). This pulse is non-slice-selective and so causes the inversion of magnetisation for all tissues. The second slice-selective inversion pulse is needed to undo the inversion applied to the tissues within the imaged slice (myocardial muscle, fat), otherwise their signals would also be suppressed. The combined effect of the two inversion pulses is therefore to invert the tissues including blood outside the imaged slice. The subsequent wash-in of inverted blood into the image slice during the TI period results in suppression of signal from the blood pool.