[niyaziacer]

SynthSeg brain MRI segmentation (Billot et al.) with optional cortical parcellation, running in Slicer's own Python.

Notes for reviewers:

• Model weights: redistributed with the permission of the SynthSeg authors B. Billot and J.E. Iglesias (e-mail, 23 October 2026). They are not in the extension package; they are downloaded on first use from the repository's models-v1 release and verified with SHA-256.
• Dependencies: on first use the module asks the user before pip-installing tensorflow==2.21 and tf-keras==2.21 into Slicer's Python, with numpy pinned to its current version. SynthSeg runs in a separate PythonSlicer process. Tested in Slicer 5.12.3 next to TotalSegmentator and OpenMAP-T1; segmentation volumes match the original TensorFlow 2.4.1 environment within 0.007%.
• The bundled SynthSeg source (Apache 2.0) is installed with the module.

New extension

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