A system and method for imaging a subject are disclosed. A plurality of edge points corresponding to a set of candidate structures are determined in each image frame in a plurality of 3D image frames corresponding to a volume in the subject. A target structure is detected from the set of candidate structures by applying constrained shape fitting to the edge points in each image frame. A subgroup of image frames including the target structure is identified from the 3D frames. A subset of edge points corresponding to the target structure is determined in each of the subgroup of image frames. A plurality of 2D scan planes corresponding to the subset of edge points is determined, and ranked using a determined ranking function to identify a desired scan plane. A diagnostic parameter corresponding to the target structure is measured using a selected image frame that includes the desired scan plane.