Method, apparatus and computer program for calculating current distribution inside brain

摘要

Apparatus for calculating current distribution inside brain includes: initial grid setting unit configured to set grid points constituting grid with predetermined pitch; current calculating unit configured to calculate current value at each grid point based on the electromagnetic information, by solving forward problem to obtain lead field matrix and by solving inverse problem to obtain current source vector; sub-grid setting unit configured to set grid points constituting sub-grid with smaller pitch, only for subset of the previously set grid, based on the current value at each grid point calculated in the preceding current calculating step; and calculation executing unit configured to repeat setting the sub-grid and calculating the current source vector by the sub-grid setting unit and the current calculating unit one or more times, after calculation of current source vector corresponding to the initial grid is executed by the initial grid setting unit and the current calculating unit.

主权项

1. A method for calculating current distribution inside a brain using a computer, based on electromagnetic information obtained from a surface of a head, the method comprising:
an initial grid setting step of setting grid points constituting a grid with a predetermined pitch; a current calculating step of calculating a current value at each of the grid points based on the electromagnetic information and an equation [L][s]=[b], where [L] is a lead field matrix, [s] is a current source vector that gives current distribution consisting of an array of currents at each of the grid points, and [b] is an electromagnetic vector including an array of the electromagnetic information, by solving a forward problem to obtain [L] and by solving an inverse problem to obtain [s]; and a sub-grid setting step of setting grid points constituting a sub-grid with a pitch smaller than that of a previously set grid, only for a subset of the previously set grid, based on the current value at each grid point calculated in the preceding current calculating step, wherein after the initial grid setting step and the current calculating step are carried out, the sub-grid setting step and the following current calculating step are repeated one or more times, and wherein the current calculating step comprises a step of solving an inverse problem [G] by calculating [Gi+1]=[Gi]+[Lsi][Lsi]T, where [Gi] is a gram matrix for the previously set entire grid, [Gi+1] is a gram matrix for the currently set entire grid, and [Lsi] is a lead field matrix for the currently set sub-grid.