.. _dwi2mask:

dwi2mask
===================

Synopsis
--------

Generates a whole brain mask from a DWI image

Usage
--------

::

    dwi2mask [ options ]  input output

-  *input*: the input DWI image containing volumes that are both diffusion weighted and b=0
-  *output*: the output whole-brain mask image

Description
-----------

All diffusion weighted and b=0 volumes are used to obtain a mask that includes both brain tissue and CSF.

In a second step peninsula-like extensions, where the peninsula itself is wider than the bridge connecting it to the mask, are removed. This may help removing artefacts and non-brain parts, e.g. eyes, from the mask.

Options
-------

-  **-clean_scale value** the maximum scale used to cut bridges. A certain maximum scale cuts bridges up to a width (in voxels) of 2x the provided scale. Setting this to 0 disables the mask cleaning step. (Default: 2)

DW gradient table import options
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

-  **-grad file** Provide the diffusion-weighted gradient scheme used in the acquisition in a text file. This should be supplied as a 4xN text file with each line is in the format [ X Y Z b ], where [ X Y Z ] describe the direction of the applied gradient, and b gives the b-value in units of s/mm^2. If a diffusion gradient scheme is present in the input image header, the data provided with this option will be instead used.

-  **-fslgrad bvecs bvals** Provide the diffusion-weighted gradient scheme used in the acquisition in FSL bvecs/bvals format files. If a diffusion gradient scheme is present in the input image header, the data provided with this option will be instead used.

Standard options
^^^^^^^^^^^^^^^^

-  **-info** display information messages.

-  **-quiet** do not display information messages or progress status; alternatively, this can be achieved by setting the MRTRIX_QUIET environment variable to a non-empty string.

-  **-debug** display debugging messages.

-  **-force** force overwrite of output files (caution: using the same file as input and output might cause unexpected behaviour).

-  **-nthreads number** use this number of threads in multi-threaded applications (set to 0 to disable multi-threading).

-  **-config key value** *(multiple uses permitted)* temporarily set the value of an MRtrix config file entry.

-  **-help** display this information page and exit.

-  **-version** display version information and exit.

References
^^^^^^^^^^

Dhollander T, Raffelt D, Connelly A. Unsupervised 3-tissue response function estimation from single-shell or multi-shell diffusion MR data without a co-registered T1 image. ISMRM Workshop on Breaking the Barriers of Diffusion MRI, 2016, 5

Tournier, J.-D.; Smith, R. E.; Raffelt, D.; Tabbara, R.; Dhollander, T.; Pietsch, M.; Christiaens, D.; Jeurissen, B.; Yeh, C.-H. & Connelly, A. MRtrix3: A fast, flexible and open software framework for medical image processing and visualisation. NeuroImage, 2019, 202, 116137

--------------



**Author:** David Raffelt (david.raffelt@florey.edu.au), Thijs Dhollander (thijs.dhollander@gmail.com) and Ben Jeurissen (ben.jeurissen@uantwerpen.be)

**Copyright:** Copyright (c) 2008-2025 the MRtrix3 contributors.

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License, v. 2.0. If a copy of the MPL was not distributed with this
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Covered Software is provided under this License on an "as is"
basis, without warranty of any kind, either expressed, implied, or
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Covered Software is free of defects, merchantable, fit for a
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See the Mozilla Public License v. 2.0 for more details.

For more details, see http://www.mrtrix.org/.


