MEG-MRI Brain Imaging group

In the MEG-MRI group, we develop techniques and instrumentation for neuroscience and medicine, electromagnetic neuroimaging in particular.

Quantum-mechanical phenomena such as superconductivity and nuclear magnetic resonance allow probing the human brain and detecting its function using magnetic fields. Developing the MEG-MRI methodology and instrumentation involves a variety of topics such as physics, electronics, neuroscience, prototyping, signal processing, mathematics and programming (most notably Python). MEG-MRI is a key part in the BREAKBEN EU Consortium aiming at dramatic improvements in electromagnetic neuroimaging.

Ultra-low-field magnetic resonance imaging (ULF MRI) is a relatively new technique, where the nuclear magnetic resonance (NMR) is measured at kHz frequencies using ultra-sensitive magnetic field sensors, typically based on superconducting quantum-interference devices (SQUIDs) and operating at a 4.2 K temperature. ULF MRI provides a completely silent and safe method for acquiring 3D images, for instance, of the human head.

Current-density imaging (CDI) maps the electric current density flowing in a volume, such as in living tissues in the human head. ULF MRI offers unique possibilities in current-density imaging, because with ultra-low-noise electronics developed in the MEG-MRI group, all the applied magnetic fields can be rapidly switched on and off during the imaging sequence. The group has also published the first CDI pulse sequences and simulations based on this technique, and we proceed to develop the technique in practice. Current-density imaging can provide valuable information for improving the accuracy of localization of electrical brain activity.

Magnetoencephalography (MEG) is the measurement of the magnetic field generated by electric currents in neuronal activity. When a large number of highly sensitive magnetic field sensors is used, one obtains information about the location of the brain activity. A great deal of MEG expertise is concentrated in the Helsinki area. The MEG-MRI group at Aalto University continues the heritage of the Low-Temperature Laboratory in applying superconductivity to brain imaging, and Elekta Oy in Helsinki is the leading manufacturer of MEG devices. The combination of MEG with ULF MRI and CDI can signifantly improve the workflow and accuracy of localizing brain activity.

The MEG-MRI Brain Imaging group collaborates with Elekta Oy and VTT to build the next-generation MEG-MRI system at Aalto (NBE) as part of the BREAKBEN EU project led by Academy Professor Risto Ilmoniemi.

For more information, contact koos.zevenhoven [at] aalto [dot] fi.

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