1. A computer-implemented method of modeling at least a portion of a patient's anatomy, using a computer system, the method comprising: determining one or more first anatomical parameters of a target anatomical object associated with a first segmentation of image data; determining one or more second anatomical parameters of the target anatomical object associated with a second segmentation of said image data; calculating one or more updated first anatomical parameters based on the one or more second anatomical parameters; and updating a model of the target anatomical object, based at least on the updated first anatomical parameters.