title: Comparison and analysis of inter-subject variability of simulated magnetic activity generated from gastric electrical activity.
abstract: Electrogastrograms (EGGs) produced from gastric electrical activity (GEA) are used as a non-invasive method to aid in the assessment of a subject's gastric condition. It has been documented that recordings of the magnetic activity generated from GEA are more reliable. Typically, with magnetic measurements of GEA, only activity perpendicular to the body is recorded. Also, external anatomical landmarks are used to position the magnetic recording devices, SQUIDs, (Superconducting Quantum Interference Devices) over the stomach with no allowance made for body habitus. In the work presented here, GEA and its corresponding magnetic activity are simulated. Using these data, we investigate the effects of using a standard SQUID location as well as a customized SQUID position and the contribution the magnetic component perpendicular to the body makes to the magnetic field. We also explore the effects of the stomach wall thickness on the resultant magnetic fields. The simulated results show that the thicker the wall, the larger the magnitude of the magnetic field holding the same signal patterns. We conclude that most of the magnetic activity arising from GEA occurs in a plane parallel to the anterior body. We also conclude that using a standard SQUID position can be suboptimal.
authors.affiliation: Bioengineering Institute, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. r.komuro@auckland.ac.nz
authors.forename: Rié
authors.initials: R
authors.lastname: Komuro
authors.forename: Leo K
authors.initials: LK
authors.lastname: Cheng
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pullan
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D003198:Computer Simulation; D004574:Electromagnetic Fields; D006801:Humans; D008280:Magnetics; D008297:Male; D008959:Models, Neurological; D009130:Muscle, Smooth / Q000502:physiology*; D016065:Myoelectric Complex, Migrating / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013270:Stomach / Q000502:physiology*