1. A method comprising: obtaining data from a magnetic resonance image device; rendering an initial image based upon said data; receiving a user selection indicative of an approximate central point of a target object comprised by said initial image; automatically determining an initial mathematical representation of said target object based upon said data, said initial mathematical representation of said target object comprising an initial contour, said initial contour based upon said approximate central point of said target object; automatically determining an updated contour of said target object based upon an application of an iterative minimization algorithm to an energy function, said energy function based upon a variogram statistic calculated from said data from said magnetic resonance image device, each iteration of said iterative minimization algorithm comprising a comparison of model variogram with an estimated variogram associated with said updated contour of said target object, said estimated variogram determined via a derivative of said energy function evaluated at a contour associated with a prior variogram model of said target object; automatically rendering said updated contour of said target object.