mri_synthmorph NAME mri_synthmorph - register 3D brain images without preprocessing SYNOPSIS mri_synthmorph [-h] command [options] DESCRIPTION SynthMorph is a deep-learning tool for symmetric, acquisition-agnostic registration of single-frame brain MRI of any geometry. The registration is anatomy-aware, removing the need for skull-stripping, and you can control the warp smoothness. Pass an option or command from the following list. You can omit trailing characters, as long as there is no ambiguity. register Register 3D brain images without preprocessing. apply Apply an existing transform to another 3D image or label map. -h Print this help text and exit. IMAGE FORMAT The registration supports single-frame image volumes of any size, resolution, and orientation. The moving and the fixed image geometries can differ. The accepted image file formats are: MGH (.mgz) and NIfTI (.nii.gz, .nii). Internally, the registration converts image buffers to: isotropic 1-mm voxels, intensities min-max normalized into the interval [0, 1], and left-inferior-anterior (LIA) axes. This conversion requires intact image-to-world matrices. That is, the head must have the correct anatomical orientation in a viewer like freeview. TRANSFORM FORMAT SynthMorph transformations operate in physical RAS space. We save matrix transforms as text in LTA format (.lta) and displacement fields as images with three frames indicating shifts in RAS direction. ENVIRONMENT The following environment variables affect mri_synthmorph: SUBJECTS_DIR Ignored unless mri_synthmorph runs inside a container. Mounts the host directory SUBJECTS_DIR to /mnt inside the container. Defaults to the current working directory. SEE ALSO For converting, composing, and applying transforms, consider FreeSurfer tools lta_convert, mri_warp_convert, mri_concatenate_lta, mri_concatenate_gcam, and mri_convert. CONTACT Reach out to freesurfer@nmr.mgh.harvard.edu or at https://voxelmorph.net. REFERENCES If you use SynthMorph in a publication, please cite us! SynthMorph: learning contrast-invariant registration without acquired images Hoffmann M, Billot B, Greve DN, Iglesias JE, Fischl B, Dalca AV IEEE Transactions on Medical Imaging, 41 (3), 543-558, 2022 https://doi.org/10.1109/TMI.2021.3116879 Anatomy-specific acquisition-agnostic affine registration learned from fictitious images Hoffmann M, Hoopes A, Fischl B*, Dalca AV* (*equal contribution) SPIE Medical Imaging: Image Processing, 12464, 1246402, 2023 https://doi.org/10.1117/12.2653251 https://synthmorph.io/#papers (PDF) Anatomy-aware and acquisition-agnostic joint registration with SynthMorph Hoffmann M, Hoopes A, Greve DN, Fischl B*, Dalca AV* (*equal contribution) Imaging Neuroscience, 2, 1-33, 2024 https://doi.org/10.1162/imag_a_00197 Website: https://synthmorph.io