ITK-SNAP Changelog

What's new in ITK-SNAP 3.6.0 RC 1

• New features:
• Multiple images with different dimensions, voxel size, and orientation can be visualized in the same ITK-SNAP window. When additional images are loaded, they are represented in memory in their native resolution, and resampled on the fly to match the screen resolution.
• This means that you can use information from two MRI modalities to guide manual segmentation. You can load a T1-weighted image with 1.0mm isotropic resolution and a T2-weighted image with 0.4mm x 0.4mm x 2.0mm resolution, and use the full information from both of these images for your segmentation.
• The manual segmentation is still performed in the voxel space of the main image.
• A new registration tool is available under Tools->Registration. The tool provides both interactive manual registration and automatic affine and rigid registration.
• Manual registration includes rotation/translation/scaling widgets and a mouse-based interactive registration mode, where moving the mouse over the 'moving' image performs rotation and translation. Rotation is performed by turning a 'wheel' widget, and very small rotations are possible. The center of rotation can be set by moving the cursor.
• Automatic registration is quite fast. It allows rigid and affine registration. It supports mutual information (inter-modality) and patch cross-correlation (intra-modality) metrics. Optionally, a mask can be provided, over which the metric is computed. It is easy to generate masks using the segmentation interpolation tool (see below). Masks are useful when the extent of the images is different, e.g., one includes neck and another does not.
• Registration results can be saved as matrix files compatible with ANTS, Convert3D and Greedy tools. Using Convert3D, they can be converted to FLIRT-compatible transform files. Registration results are also automatically saved in workspace files.
• DICOM functionality is greatly improved.
• After you load a 3D volume from a DICOM image directory, you can load other 3D volumes in the same directory quickly using the new File->Add Another DICOM Series submenu.
• Listing of DICOM directories (in the Open Image wizard) is much faster than before. This really makes a difference when opening images on DVDs and USB sticks.
• Dragging and dropping a DICOM file onto the ITK-SNAP window on Windows and Mac now shows the list of 3D volumes in the directory, allowing you to choose a volume to open.
• A new tool for interpolating segmentations between slices under Tools->Interpolate Labels.
• For images with thin slices and gradually changing anatomy, you can segment every fifth slice and fill in the missing slices using this new tool. Details of the algorithm are provided in an Insight Journal article.
• Label visibility can be changed 'en masse' in the Label Editor, i.e., you can make all labels visible or hidden. This helps find a label in segmentation with many labels that occlude each other.
• Programmatic Enhancements:
• ITK-SNAP now includes Convert3D and Greedy registration tools as submodules. This is already used to support registration functionality, but in the future we will be adding more Convert3D-based functionality, such as filtering, etc.
• Bug Fixes:
• Fixed issue with Workspace->Save As... where you would be asked to save the current workspace (thx Laura W).
• Fixed issue where DICOM data was not loading correctly when workspace was moved in the filesystem (thx Vincent F).
• Fixed issue with loading of NRRD images on some systems due to non-US locale (thx Johan B)
• Fixed behavior of Ctrl-W, so that when there are open dialog windows this keystroke closes them rather than the current image layer (thx Karl B)
• Fixed issue with multi-component images, where every 100th component showed up as 'Magnitude' (this Phil. C)
• Fixed OpenGL rendering issues on Windows 10 on some cards
• Fixed computation of zoom factor on Retina displays
• Fixed behavior of File Save browse dialogs on MacOS when saving .nii.gz files
• Fixed issues with unnecessary prompting to save segmentations
• Several other fixes for specific crashes.