SYSTEM AND METHOD FOR MEASURING, ESTIMATING AND DISPLAYING RMS CURRENT DENSITY MAPS

摘要

A method of performing synthetic aperture magnetometery on the signals from a target organ using an array of biomagnetic sensors positioned in a predetermined manner around the target organ, each sensor in the array having a position vector and an orientation vector relative to a common coordinate system encompassing the target organ. The method comprises the steps of: (i) simultaneously measuring EM signals from each sensor positioned in the array for a selected time interval; (ii) computing a covariance matrix of the measured EM signals over a user-selected time sub-interval within the selected time interval; (iii) selecting a set of coordinates for a region of interest to be imaged and a distance between voxels to form a grid of voxels; (iv) computing a forward solution for a current element at each of the voxels for each of the sensors in the array sensors; (v) computing an RMS current density estimate for each voxel from the covariance matrix and the forward solution for that voxel; and (vi) displaying the voxels estimating RMS current density as a first image. The method is particularly well suited for evaluating brain activity in a human subject.