Variability and bias between magnetoencephalography systems in localization of the primary visual cortex

Lindsey Power; Marc Lalancette; Ronald Bishop; Steven Beyea; Margot J Taylor; Benjamin T Dunkley; Timothy Bardouille

doi:10.1016/j.clineuro.2020.105746

Variability and bias between magnetoencephalography systems in localization of the primary visual cortex

Clin Neurol Neurosurg. 2020 Jul:194:105746. doi: 10.1016/j.clineuro.2020.105746. Epub 2020 Feb 24.

Authors

Lindsey Power¹, Marc Lalancette², Ronald Bishop³, Steven Beyea⁴, Margot J Taylor⁵, Benjamin T Dunkley⁶, Timothy Bardouille⁷

Affiliations

¹ Biomedical Translational Imaging Centre (BIOTIC), IWK Health Centre, 5980 University Street, Halifax, NS, B3K 6R8, Canada. Electronic address: lindsey.power@dal.ca.
² Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada. Electronic address: marc.lalancette@sickkids.ca.
³ Biomedical Translational Imaging Centre (BIOTIC), IWK Health Centre, 5980 University Street, Halifax, NS, B3K 6R8, Canada. Electronic address: ronald.bishop@iwk.nshealth.ca.
⁴ Biomedical Translational Imaging Centre (BIOTIC), IWK Health Centre, 5980 University Street, Halifax, NS, B3K 6R8, Canada; Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Road, Halifax, NS, B3H 4R2, Canada; Department of Diagnostic Radiology, Dalhousie University, Room 319, Victoria Building, 1276 South Park St, Halifax, NS B3H 2Y9, Canada. Electronic address: steven.beyea@iwk.nshealth.ca.
⁵ Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada. Electronic address: margot.taylor@sickkids.ca.
⁶ Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada; Neurosciences & Mental Health, The Hospital for Sick Children Research Institute, Toronto, ON, Canada; Department of Medical Imaging, University of Toronto, Toronto, ON, Canada. Electronic address: ben.dunkley@sickkids.ca.
⁷ Biomedical Translational Imaging Centre (BIOTIC), IWK Health Centre, 5980 University Street, Halifax, NS, B3K 6R8, Canada; Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Road, Halifax, NS, B3H 4R2, Canada; Department of Diagnostic Radiology, Dalhousie University, Room 319, Victoria Building, 1276 South Park St, Halifax, NS B3H 2Y9, Canada. Electronic address: tim.bardouille@dal.ca.

PMID: 32217371
DOI: 10.1016/j.clineuro.2020.105746

Abstract

Objectives: When using MEG for pre-surgical mapping it is critically important that reliable estimates of functional locations, such as the primary visual cortex (V1) can be provided. Several different models of MEG systems exist, each with varying software and hardware configurations, and it is not currently known how the system type contributes to variability in V1 localization.

Patients and methods: In this study, participants underwent MEG sessions using two different systems (Vector View and CTF) during which they were presented with a repeating grating stimulus to the lower-left visual quadrant to generate a visual evoked field (VEF). The location, amplitude and latency of the VEF source was compared between systems for each participant.

Results: No significant differences were found in latency and amplitude between systems, however, a significant bias in the latero-medial position of the localization was present. The median inter-system Euclidian distance between V1 localization across participants was 10.5 mm.

Conclusions: Overall, our results indicate that mapping of V1 can be reliably reproduced within approximately one centimetre by different MEG systems.

Significance: This result provides knowledge of the useful limits on the reliability of localization which can be taken into consideration in clinical practice.

Keywords: Bias; Magnetoencephalography; Pre-surgical mapping; Primary visual cortex; Variability; Visual evoked field.

MeSH terms

Adult
Bias
Brain Mapping / methods
Evoked Potentials, Visual
Female
Humans
Magnetic Resonance Imaging
Magnetoencephalography / statistics & numerical data*
Male
Photic Stimulation
Reproducibility of Results
Software
Visual Cortex / diagnostic imaging
Visual Cortex / physiology*
Visual Fields
Young Adult