ITK-SNAP

ITK-SNAP is an interactive open-source application for segmenting structures in 3D and 4D medical images. It provides semi-automatic segmentation using active contour methods, as well as manual delineation and image navigation, and a number of supporting utilities. ITK-SNAP has over 10,000 monthly downloads and is used by hundreds of research groups around the world. ITK-SNAP development is led by Paul Yushkevich.