Extraslice spin tagging (EST) magnetic resonance imaging for the determination of perfusion

A new magnetic resonance technique to measure perfusion is described in det ail. The means by which this is done is to invert all the spins in the radi ofrequency RF coil with a non-spatially selective pulse and immediately re- invert the spins in the imaging plane, The net effect is that the spins in the imaging plane experience minimal perturbation of their magnetization wh ile the spins outside the plane (extraslice) are inverted, or tagged, Tagge d spins that now into the imaging plane before image data are acquired decr ease the signal intensity in the imaging plane when compared with an image in which the inflowing spins are not tagged. This decrease in signal can be used to calculate the number of spins that have flowed into the imaging pl ane, i.e., can be used to calculate the perfusion in mt 100 g(tissue)(-1) . min(-1). The extraslice spin tagging (EST) magnetization preparation perio d was coupled with a fast imaging sequence to obtain perfusion maps for nor mal volunteers. J. Magn. Reson. Imaging 1999;9:146-150. (C) 1999 Wiley-Liss , Inc.