fMRI Motion Estimation

Activation Artifact

Bold activation in the visual cortex (left) together with the stimulus response plotted against image gradient.

These demonstrations show the correlation based analysis of time course data from a functional MR activation study.  In particular we show a new technique for automatic assessment of the adequacy of motion correction.   The method is based on the principle that any motion artifact must be proportional to the local image gradient and involves producing a scatter-gram of correlation score against image gradient. Using this data the effects of motion on the results of fMRI correlation based analysis can be directly evaluated even for unknown motion. We show how motion affects three correlation approaches which are statistically equivalent to the majority of alternative parametric methods in the literature

Library toolkit
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Sun Sparc - Solaris 2
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Intel x86 - Linux 2
[1] N A Thacker, E Burton, A J Lacey, and A Jackson, `The effects of motion on parameteric fMRI analysis techniques', Physiological Measurement, 20(3), August 1999.
[2] A J Lacey, N A Thacker, E Burton, and A Jackson `How to locate motion artifacts in parametric fMRI analysis', In Proc. of MIUA, July 1999
[3] A J Lacey, N A Thacker, E Burton, and A Jackson. `Locating motion artifacts in parametric fMRI analysis', In Proc. of MICCAI, volume LNCS 1679, pages 524-532, September 1999.
Relevant other work
[4] E.Bullmore, M.Brammer, S.C.R.Williams, S. Rabe - Hesketh, N.Janot, A.David, J.Mellers, R.Howard, P.Sham., `Statistical Methods of Estimation and Inference for Functional MR Image Analysis', MRM, 35, 261-277, 1996.
[5] K.J.Friston, J. Ashbuner, C.D.Frith, J.B.Poline, J.D.Heather, R.S.J.Frackowiak, `Spatial Registration and Renormalisation of Images', MBM, 2, 165-188 1995.
[4] O. Presciutti, G.P. Pelliccioli, R.Tarducci, P.Chiarinic and G.Gobbi., `New Processing Methods in Functional MRI' Rivista di Neuroradiologica, 10, 261-264, 1997.
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