1. A method of determining an accuracy of shape-determining processes for identifying shapes of a body tissue in one or more images of a patient, the method comprising: receiving first data that defines a first boundary of a first shape of the body tissue in at least a portion of the one or more images, the first shape being determined by a first shape-determining process, wherein the one or more images are diagnostic images of the patient; receiving second data that defines a second boundary of a second shape of the body tissue in at least a portion of the one or more images, the second shape being determined by a second shape-determining process; placing the first shape and the second shape within a coordinate space; determining, by a computer system, an intersection shape of the first shape and the second shape in the coordinate space; determining, by the computer system, a union shape of the first shape and the second shape in the coordinate space; calculating, by the computer system, a difference between the union shape and the intersection shape; computing, by the computer system, a shape similarity metric based on the difference; and providing the shape similarity metric for determining an accuracy of the second shape-determining process relative to the first shape-determining process.