Electroencephalography

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Figure Caption: Illustration of EEG recording capabilities inside a 3T Siemens MRI scanner using a Neuroscan Maglink system. Both windows show the exact same data signal. The left window shows the raw EEG signal with the high voltage artifact from the MRI scanner. The right window shows the clean EEG signal after the artifact has been removed in real time.
Future Directions

Work is underway in collaboration with Compumedics-Neuroscan to adapt the existing Maglink system to enable diagnostic ECG recordings inside the 3T MRI scanner. Trials are set to begin in early 2010. If successful, this system will be the first of its kind worldwide and provide cardiologists with valuable information about cardiac function while imaging the brain. Equally ambitious, we have plans to combine MRI, EEG and PET technologies in collaboration with Neuroscan and Siemens. Such an approach will provide a wealth of diagnostic information to clinicians.

The CFI-funded electroencephalography (EEG) labs have recently been established within Lawson Imaging, a product of a long-term partnership between Siemens Canada, Compumedics-Neuroscan and Lawson The labs focus on the use of high density EEG systems (128 channel 3T MR/PET/EEG and others) to perform Event-Related Potential (ERP) recordings in a plethora of paradigms investigating the CNS pathways in health and disease. Researchers can perform simultaneous functional imaging and cortical source reconstruction or even spectral analysis to understand how the brain reacts to external stimuli and which exact area in the brain is recruited for this purpose. The EEG can be recorded inside the Siemens 3T MRI scanner as well as in the existing zero Tesla shielded  (and matching sham) booths at Lawson. The available systems can also be adapted to measure other electrophysiological measures such as electromyography (EMG) and electrocardiography (ECG). Non-physiological signals can be fed into the amplifier and synchronized with the electrophysiological signals.

Researchers
A.W. Thomas
Director, BEMS Group, Neuromodulation
A. Legros
BEMS, Kinesiology
R.Z. Stodilka
Neuronal Networks, MTBI
F.S. Prato
BEMS, Lawson Imaging Program leader, Medical Physics
Technologies
3T PET/MR
Bioelectromagnetics

Collaborators
J. Théberge
Magnetic Resonance Physics
R.T. Thompson
MR Spectroscopy
Key Accomplishments

The EEG lab at Lawson Imaging has been chosen as the premier test site for Compumedics-Neuroscan. Neuroscan’s beta software and hardware will undergo extensive testing in the lab before becoming commercially available. As such, the EEG lab has been chosen as one of 4 centers worldwide to receive Neuroscan’s latest breakthrough technology which allows clock synchronization between the 3T MRI scanner and the Compumedics-Neuroscan’s amplifier. Such synchronization is aimed at bringing the clocks of the EEG amplifier and the MRI scanner to operate under the exact same frequency, hence enabling a superior scanner artifact rejection and yielding an exceptionally clean EEG signal inside the magnet. The EEG lab has also been chosen by the Canadian Department of National Defence to assess the use of ERP technology as a means to evaluate mild traumatic brain injury (MTBI). A primary application is in assessing the readiness of soldiers who have endured a traumatic episode during combat operations.

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