a method comprises digitally representing a volume of space as a plurality of voxels and assigning real and imaginary values derived from magnetic resonance imaging data of the space to each of the voxels . furthermore , the method comprises a steps of calculating a first complex summation of the real and imaginary values of a first set of the voxels , and calculating a second complex summation of the real and imaginary values of a second set of the voxels . each set of voxels represents a different region of the volume of space . the regions are concentric . the method also comprises steps of using the first and second summations , along with another value quantitatively calculated from the magnetic resonance imaging data , to calculate a value that is dependent upon the approximate magnetic moment of an object within the volume of space , and digitally representing and storing said value .