ITK-SNAP

ITK‑SNAP is an open‑source application for segmenting structures in three‑dimensional and four‑dimensional biomedical images. It offers semi‑automatic segmentation through active contour methods and manual delineation tools, allowing users to draw segmentations simultaneously in three orthogonal planes while navigating the volume with a linked cursor. The software supports a wide range of image formats such as NIfTI and DICOM, and can handle color, multi‑channel, and time‑resolved datasets.

The interface is built on Qt6 and emphasizes ease of use, providing features like concurrent linked viewing of multiple images, between‑slice interpolation, and a 3D cut‑plane tool for post‑processing. Advanced capabilities include manual and automatic image registration and access to additional algorithms via a distributed segmentation service. Extensive tutorials and video documentation are available to help new users.

Developed originally at the University of North Carolina and now maintained by the Penn Image Computing and Science Laboratory, ITK‑SNAP focuses narrowly on image segmentation, keeping extraneous functionality to a minimum while delivering a modern, cross‑platform experience for researchers and clinicians working with medical imaging data.