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 compatible with

 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 explicit format
                  is given, it is determined automatically from the filename.
   'outputfield' = string specifying the name of the field in the
                  structure in which the numeric data is stored. The
                  default is 'anatomy'

 The following values apply for the dataformat
   'afni_head'/'afni_brik'      uses AFNI code
   'analyze_img'/'analyze_hdr'  uses SPM code
   'analyze_old'                uses Darren Webber's code
   'dicom'                      uses FreeSurfer code
   'dicom_old'                  uses own code
   'freesurfer_mgh'             uses FreeSurfer code
   'freesurfer_mgz'             uses FreeSurfer code
   'matlab'                     assumes a MATLAB *.mat file containing a mri structure according to FT_DATATYPE_VOLUME
   'minc'                       uses SPM (<= version SPM5)
   'neuromag_fif'               uses MNE toolbox
   'neuromag_fif_old'           uses meg-pd toolbox
   'nifti'                      uses FreeSurfer code
   'nifti_fsl'                  uses FreeSurfer code
   'nifti_spm'                  uses SPM
   'mrtrix_mif'                 uses mrtrix code

 The following MRI file formats are supported
   CTF (*.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/Megin (*.fif)
   ANT - Advanced Neuro Technology (*.mri)
   Yokogawa (*.mrk, incomplete)
   Mrtrix image format (*.mif)

 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