1. A method for automatically segmenting a three-dimensional image depicting a subject, the three-dimensional image being acquired with a magnetic resonance imaging (MRI) system, the steps of the method comprising: a) acquiring with the MRI system, image data from a subject; b) reconstructing from the image data acquired in step a), a three-dimensional image depicting the subject and a volume-of-interest to be segmented; c) producing from the three-dimensional image reconstructed in step b), a monogenic signal that represents the three-dimensional image; d) analyzing the monogenic signal produced in step c) to determine locations in the three-dimensional image that correspond to points of maximal phase congruency; e) determining an orientation of each of the points of maximal phase congruency determined in step d); f) estimating a surface of the volume-of-interest using the determined points of maximal phase congruency and the determined orientation of each of the points of maximal phase congruency; g) segmenting the volume-of-interest from the three-dimensional image using the estimated surface of the volume of interest.