1. A method for automatic contrast enhancement for contouring, comprising: displaying a volumetric image slice to be analyzed; receiving a user delineation of a target anatomic structure in the volumetric image slice; identifying a region of interest based upon an area being delineated in the volumetric image slice, wherein if the user delineation is not received, the method identifies the entire volumetric image slice as the region of interest; analyzing voxel intensity values in the region of interest; and determining an appropriate window-level setting based on the voxel intensity values, wherein the region of interest is continuously identified, the voxel intensity values of the region of interest analyzed and the appropriate window-level setting determined as the target anatomic structures is delineated.