Brain disorders cause a great deal of suffering and a major economic burden to society; the annual cost in Europe alone has been estimated at €800bn. The goal of the Horizon 2020 Future and Emerging Technologies project BREAKBEN is to dramatically improve the accuracy of magnetoencephalography (MEG) in characterising electrical activity in the brain. This will be done by combining MEG with another powerful electromagnetic imaging technology, magnetic resonance imaging (MRI). By measuring the ultra-weak magnetic fields generated by the brain, MEG can non-invasively inform us about neuronal function. MRI, on the other hand, maps the tissue- dependent behaviour of nuclear spins in water molecules, providing accurate structural images. The simultaneous measurement of both MEG and MRI will be key to improving diagnostic information.
In BREAKBEN, superconducting SQUID-sensor arrays will be used. The MRI signals are recorded at far weaker magnetic fields than the usual convention, i.e. at about 100 microtesla instead of several tesla. BREAKBEN’s predecessor, the MEGMRI project (2008-2012), indicated that a clinically useful hybrid MEG-MRI system may be possible. The challenge is huge, since the signal- to-noise ratio in the MRI measurement must still be improved by a factor of at least 1,000 in circumstances where the relevant magnetic field strengths cover a range from 1 femtotesla to 0.1 tesla or 14 orders of magnitude.
The new technology is expected to improve, for example, the mapping of epileptic brain activity. It may also enhance the diagnosis of cancer patients thanks to improved image contrast at ultra-low MRI fields. The MEG-MRI device will also open brain imaging for new patient groups, such as those with metal implants. Cost reductions may be expected thanks to improved workflow and more accurate diagnostics that can shorten hospital stays and optimise treatment. Furthermore, there is hope that the new device can be used to measure the conductivity structure of the brain, which would improve the accuracy of locating brain activity with MEG as well as with EEG. This would also enable further improved accuracy in transcranial magnetic stimulation (TMS) of the brain, a technique also under further development at Aalto University.
The co-ordinator of BREAKBEN, Aalto University, together with Elekta, will build the hybrid device. The VTT Technical Research Centre of Finland will develop a new generation of optimised SQUID-sensors. The technology will be used by the BioMag Laboratory of the Helsinki University Hospital in patient trials and by University of Chieti-Pescara in studies of brain connectivity. In a highly ambitious development taking place at Physikalisch-Technische Bundesanstalt, Berlin, scientists intend to make another breakthrough by detecting neuronal currents by nuclear magnetic resonance (NMR) techniques, a task often considered nearly impossible but now within reach. Sophisticated ‘phantoms’ will be developed by Ilmenau University of Technology to mimic the properties of the human head and brain in order to allow testing of the sensitivity and accuracy of the developed instruments.
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PT Vesanen et al., Hybrid ultra-low-field MRI and magnetoencephalography system based on a commercial whole-head neuromagnetometer, Magn. Reson. Med. 69:179 (2013).
Department of Neuroscience and Biomedical Engineering
Aalto University School of Science
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