B. Hochwald et A. Nehorai, MAGNETOENCEPHALOGRAPHY WITH DIVERSELY ORIENTED AND MULTICOMPONENT SENSORS, IEEE transactions on biomedical engineering, 44(1), 1997, pp. 40-50
To locate endocranial current sources, a magnetoencephalography (MEG)
system usually measures the magnetic field at many points around the s
kull with an array of radial sensors, Despite the success of using rad
ial components of the field, we show that using nonradial components m
ay potentially also be beneficial. We demonstrate some benefits of usi
ng diversely oriented and multicomponent sensors to measure the nonrad
ial components, A framework is provided for analyzing the accuracy of
a system that estimates the location and direction of a current dipole
inside a spherical skull, The framework is then used to determine the
effect on accuracy of varying the orientations of sensors in an array
and, as a consequence, it is found that the radial orientations commo
nly used in practice are suboptimal for locating dipoles near the arra
y's tenter. A diversely oriented array that improves performance is pr
esented. We show how a single multicomponent sensor can locate a dipol
e, and derive a simple algorithm for locating a dipole near the sensor
.