Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_read_mri”.

  FT_READ_MRI reads anatomical and functional MRI data from different
  file formats. The output data is structured in such a way that it is
  comparable to a FieldTrip source reconstruction.
  Use as
    [mri] = ft_read_mri(filename)
  Additional options should be specified in key-value pairs and can be
    'dataformat' =  string specifying the file format, determining the low-
                    level reading routine to be used. If no format is given,
                    it is determined automatically from the file.
                    The following formats can be specified:
                         'afni_head'/'afni_brik'      uses afni
                         'analyze_img'/'analyze_hdr'  uses spm
                         'analyze_old'                uses Darren Webber's code
                         'dicom'             uses freesurfer
                         'dicom_old'         uses own code
                         'freesurfer_mgh'    uses freesurfer
                         'freesurfer_mgz'    uses freesurfer
                         'minc'              uses spm (<= version spm5)
                         'nifti'             uses freesurfer
                         'nifti_fsl'         uses freesurfer
                         'nifti_spm'         uses spm
                         'neuromag_fif'      uses mne toolbox
                         'neuromag_fif_old'  uses meg-pd toolbox
                         'matlab'            assumes a MATLAB *.mat file containing a mri structure
                                             according FieldTrip standards
  The following MRI file formats are supported
    CTF - VSM MedTech (*.svl, *.mri version 4 and 5)
    NIFTi (*.nii) and zipped NIFTi (*.nii.gz)
    Analyze (*.img, *.hdr)
    DICOM (*.dcm, *.ima)
    AFNI (*.head, *.brik)
    FreeSurfer (*.mgz, *.mgh)
    MINC (*.mnc)
    Neuromag - Elekta (*.fif)
    ANT - Advanced Neuro Technology (*.mri)
    Yokogawa (*.mrk, incomplete)
  If you have a series of DICOM files, please provide the name of any of the files 
  in the series (e.g. the first one). The other files will be found automatically.
  The output MRI may have a homogenous transformation matrix that converts
  the coordinates of each voxel (in xgrid/ygrid/zgrid) into head