FASTMAP shimming

on Varian INOVA systems

FASTMAP is a shimming technique based on measuring B0 field plots along projections instead of mapping whole imaging planes with the benefit of improved speed and performance.

IMPORTANT: By using FAST(EST)MAP, the users agree to cite the following in their publications:
Gruetter R, Magn. Reson. Med. 29,804-811 (1993)
[PDF file (617k)]
(and, possibly, Gruetter and Tkac, Magn. Reson. Med. 43, 319-324 (2000).), [PDF file (152k)]

Background literature

First, see Gruetter R, Magn. Reson. Med. 29,804-811 (1993) and refs. therein
for a description of the underlying theory see also Gruetter R and Boesch C, J. Magn. Reson. 96,323-334 (1992) [PDF file (871k)]
Further papers dealing with more aspects of FASTMAP, see alo Shen et al. Magn. Reson. Med. 38:834 (1997) and Gruetter et al., J. Magn. Reson. 135, 260-264 (1998)
For a description of the FAST(EST)MAP modification, please see Gruetter and Tkac, Magn. Reson. Med. 43, 319-324 (2000

To download FASTMAP click here.

On how to INSTALL and CALIBRATE FASTMAP  click here.

For general information on FASTMAP, click here.

Initial setup:  click here.

For parameters that need more frequent ("daily") adjustments, click here.

For an example of how to run FASTMAP (4 Tesla), click here.

Assessing FASTMAP performance

Troubleshooting FASTMAP


Note that the success of this shim procedure assumes that your specific localization sequence is devoid of any eddy current effects. If eddy currents persist as can be judged from convergence of FASTMAP and substantial linewidths and -distortions in the localized sequence, manual adjustment of liner shims should provide substantial improvement. Proper adjustment of eddy current compensation is highly recommended however. See e.g. Terpstra et al. J. Magn. Reson. 131:139 1998 and refs therein [PDF file (120k)].