1. An apparatus for detecting an error in a contour of a lesion, the apparatus comprising: an extracting unit configured to extract a contour of a lesion in each of a plurality of two-dimensional image frames that form a three-dimensional image; and an error determining unit configured to determine a presence or an absence of an error in the contour of the lesion in a target image frame of the two-dimensional image frames based on estimation information about the lesion in the target image frame and/or an energy value that corresponds to the contour of the lesion in the target image frame.