@CONFERENCE\{IMM2005-03595, author = "D. A. Holm and K. Sidaros", title = "ASL: Comparison of presaturation and {RF} pulse optimization", year = "2005", month = "may", pages = "1153", booktitle = "Proc. International Society of Magnetic Resonance In Medicine - {ISMRM} 2005, Miami, Florida, {USA}", volume = "", series = "", editor = "", publisher = "", organization = "", address = "", url = "http://www2.compute.dtu.dk/pubdb/pubs/3595-full.html", abstract = "In arterial spin labelling, the difference between the tag and control image is on the order of 1\% of the equilibrium magnetization. A small offset between the images not related to perfusion, can therefore lead to large errors in the measured perfusion. One source of error is non-ideal {RF} pulses resulting in the inversion pulse affecting the acquired signal from the imaging area. This systematic error can be reduced by increasing the gap between the inversion and imaging regions, by using optimized inversion pulses e.g. FOCI1 or by saturating the signal from static tissue in the imaging area prior to acquiring the image. In this simulation study, the use of presaturation is compared with using optimized {RF} pulses. Furthermore the effect of using and optimizing crusher gradients is reported." }