Analytic solution to boundary integral computation of susceptibility induced magnetic field inhomogeneities

A method to compute the magnetic field induced by susceptibility inhomogeneities in magnetic resonance imaging is presented. It is based on a boundary integral representation formulae. The integral is set over the surfaces between media of different magnetic susceptibilities. The computational procedure consists of approximating these surfaces with triangular mesh elements and using analytical expressions to compute the integral over each triangle. The proposed method supplies high accuracy and is easily paralleled. A detailed analysis for the convergence rate of the method is performed. Numerical results obtained for several samples, including a human head, are presented.