read.dti.grad

Reads a diffusion gradient table in MRtrix format: a plain text
file with one line per DWI volume, each line holding the four
space-separated values <code>[ x y z b ]</code>, with the direction in scanner
space and the b-value in s/mm^2. This is the format expected by the
<code>-grad</code> option of the MRtrix3 commands (and produced by
<code>-export_grad_mrtrix</code>), and it is also the format in which MRtrix3 stores
the table in the <code>dw_scheme</code> entry of a <code>.mif</code> header. A first line
consisting of a single integer is accepted as a volume count header.

Provides functions to read and write neuroimaging data in various file formats, with a focus on 'FreeSurfer' formats. This includes, but is not limited to, the following file formats: 1) MGH/MGZ/NIFTI format files, which can contain multi-dimensional images or other data. Typically they contain time-series of three-dimensional brain scans acquired by magnetic resonance imaging (MRI). They can also contain vertex-wise measures of surface morphometry data. The MGH format is named after the Massachusetts General Hospital, and the MGZ format is a compressed version of the same format. 2) 'FreeSurfer' morphometry data files in binary 'curv' format. These contain vertex-wise surface measures, i.e., one scalar value for each vertex of a brain surface mesh. These are typically values like the cortical thickness or brain surface area at each vertex. 3) Annotation file format. This contains a brain surface parcellation derived from a cortical atlas. 4) Surface file format. Contains a brain surface mesh, given by a list of vertices and a list of faces.

Tim Schc3<a4>fer

freesurferformats

Read and Write 'FreeSurfer' Neuroimaging File Formats

Tim Schäfer

Van Essen Lab 

Montreal Neurological Institute (MNI) 

read.dti.grad function

<dl><dt>filepath</dt>
<dd>character string, path to the file. There is no fixed file
name convention, <code>grad.b</code> and <code>encoding.b</code> are common. Gzip-compressed
files are supported.</dd>
<dt>layout</dt>
<dd>character string, one of 'auto', 'components' or 'volumes'.
<code>volumes</code> means one volume per line (4 values per line, the MRtrix layout),
<code>components</code> the transposed variant (4 lines). With 'auto' (the default),
the layout is derived from the matrix dimensions.</dd></dl>

Arguments

Read a gradient table in MRtrix3 format. — read.dti.grad

<dl>

<dt>filepath</dt>
<dd>character string, path to the file. There is no fixed file
name convention, <code>grad.b</code> and <code>encoding.b</code> are common. Gzip-compressed
files are supported.</dd>


<dt>layout</dt>
<dd>character string, one of 'auto', 'components' or 'volumes'.
<code>volumes</code> means one volume per line (4 values per line, the MRtrix layout),
<code>components</code> the transposed variant (4 lines). With 'auto' (the default),
the layout is derived from the matrix dimensions.</dd>

</dl>

read.dti.grad: Read a gradient table in MRtrix3 format.

Description

Usage

Value

Arguments

See Also