Clinical Potential of MagnetoEncephaloGraphy Antti Ahonen Elekta Oy Helsinki, Finland Sensing Opportunities for Diagnostics In Healthcare and Wellbeing Micronova November 20th, 2012
Basics of MEG and EEG Cellular currents in an active neuron population...... give rise to extracranial electric potentials and magnetic fields Electroencephalography (EEG) - measuring the potential differences on the scalp Magnetoencephalography (MEG) - measuring the extracranial magnetic fields
Sensor Optimization History: Development of Elekta s Multi-Channel MEG Instrumentation 1983 by HUT 4 channels 30 mm in diameter (coverage: 7 cm 2 ) Axial g.m. 1986 by HUT 7 channels 93 mm in diameter (coverage: 68 cm 2 ) Axial g.m 1989 by HUT 24 channels 125 mm in diameter (coverage: 123 cm 2 ) Planar g.m. 1992 by Neuromag 122 channels whole head (coverage: 1100 cm 2 ) Planar grad. meters 12 Deliveries 1998 by Neuromag 306 channels whole head (coverage: 1220 cm 2 ) Planar grad.meters + Magnetometers
Elekta Neuromag TRIUX
Elekta Neuromag TRIUX
Magnetic Shielding Magnetic Interference typically 10 6 10 7 times larger (~1 µt vs. max 1 pt) than the signals of interest => Magnetically Shielded Room, MaxShield TM Noise Cancellation Algorithms, MaxFilter TM With move-comp, elimination of uncorrelated noise External magnetic field MSR
MaxFilter : Head Motion compensation Movement of a six Months Old Subject [Uutela & Taulu, 2001]
Examples of Clinical Applications of MEG: Presurgical Functional Mapping Mäkelä & al., HUCH
MEG-mapping: Grade II Glioma
Examples of Clinical Applications of MEG: MEG-studies on Epileptic Patients
Focal Frontal Lobe Epilepsy with Ectopic Cortex [Dr. N.Nakasato, Tohoku University, School of Medicine, Sendai, Japan]
Integrated Video and MEG recording on an ictal pediatric patient
Examples of Clinical Applications of MEG: MEG-Studies on Deep Brain Stimulation in Parkinson s disease Mäkelä, Pekkonen & al., HUCH, 2007
Example of interference reduction Parkinsonian Patient with Subthalamic Stimulator R L
Spontaneous activity with Stimulator ON, 30 s of Raw Data LF Vx LO EOG
Spontaneous activity with Stimulator ON after tsss LF Vx LO EOG
MaxFilter : Removal of DBS artifact, Parkinsonian patient SEF dipole moments, Characteristic finding red: DBS stimulator on blue: DBS stimulator off [Courtesy of Dr. J. Mäkelä and Dr. E. Pekkonen, BioMag Laboratory, Helsinki Finland]
Examples of Clinical Applications of MEG: MEG-studies on low-frequency foci in Stroke Helle, Mäkelä et al., 2011
Active clinical research PubMed, over 2000 references Estimating recovery after CNS lesion Mild head Trauma Other Neurological disorders Dementia (Alzheimer s and Parkinsonian), Depression, Stroke and Transient Ischemic Attack (TIA), Pain Migraine, Headache, Movement disorders and MS Learning disorders and Dyslexia Psychological and psychiatric disorders Autism, Schizophrenia Developmental disorders Pharmaceutical testing Effect of drugs
Networks: The most potential MEG application? Palva, Palva et al. 2011 MNE-source distr., Phase coherence between MNI-brain areas. Working mem. task
Elekta Neuromag - leader in whole-head MEG Salt Lake City San Diego Albuquerque Boston Pittsburgh Chicago Cleveland Omaha Milwaukee Philadelphia Seattle Bethesda Halifax Cambridge Fort Worth Houston Secaucus Summit Orlando Austin NA 20 Orders received (October 2012) Espoo Helsinki Brussels Cambridge Oxford Heidelberg Leipzig Jena Alexandroupoli Paris Trento Düsseldorf (upgr) Moscow Amsterdam Donostia Paris Grenoble Madrid Riyadh Aarhus Birmingham Milan Europe and Middle East 22 Shijiazhuang Seoul Taipei Beijing Sanbo Beijing XuanWu Kota Bharu (Malaysia) Shanghai Melbourne Bangalore Gurgaon Asia/Pacific 10 Sapporo (2) Akita Tokorozawa Niigata Tokyo (2) Chiba Kyoto Gunma Okazaki Osaka (2) Komaki Japan 21 Hiroshima Yamagata Fukuoka Kawagoe Minamata Choju Miyazaki *To be installed
Thank you very much!