Specific Issues Related to EEG-fMRI at B 0 > 3 T

Abstract

Functional MRI (fMRI) can be used to map regional changes in cerebral blood flow and the level of haemoglobin oxygenation (BOLD) associated with neuronal activity (Belliveau et al. 1991; Kwong et al. 1992; Ogawa et al. 1992). In 2003 the US Food and Drug Administration raised the value of the static field of “no significant risk” for MRI to 8 Tesla (T), potentially opening up this technology to large numbers of laboratories in the USA. Regulatory agencies in Europe and Asia reached similar conclusions, and as a result the number of high-field systems worldwide is growing rapidly. The increased static field B 0 allows the potential for improved signal-to-noise ratio (SNR), offering the possibility of increasing spatial resolution and reducing scan times (Wiesinger et al. 2006; Harel et al. 2006). In this chapter, we outline the safety issues raised and the challenges involved in performing EEG at high-field MRI or at static magnetic fields greater than 3 T.