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24 April 2002 Position-history and spin-history artifacts in fMRI time series
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Abstract
What is the impact of the spin history and position history on signal intensity after the alignment of acquired volumes? This question arises in many fMRI studies. We will focus on spin-history artefacts generated by the position-history of the scanned object. In fMRI an object is driven to steady state by applying a few dummy scans at the start of each measurement. A change in object position will disrupt the tissue's steady state magnetization. The disruption will propagate to the next few acquired volumes until a steady state is reached again. The variables which are involved in changing the longitudinal magnetization are: the shape and the position of the slice profiles, the times at which RF pulses occurred, the equilibrium magnetization map and the T1 map. Knowledge of these variables enables the prediction of those situations and the locations where the spin-history may compromise the fMRI analysis. In this paper we present a simulation of spin-history artefacts. The simulation shows that these effects, following a displacement, are similar to the transient period at the beginning of the measurement. Introducing gaps between the acquired slices increases these artefacts.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Lucian Muresan, Remco Renken, Jos B.T.M. Roerdink, and Hendrikus Duifhuis "Position-history and spin-history artifacts in fMRI time series", Proc. SPIE 4683, Medical Imaging 2002: Physiology and Function from Multidimensional Images, (24 April 2002); https://doi.org/10.1117/12.463613
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