Use track data as a form of contrast for producing a high-resolution image
tckmap [ options ] tracks output
- tracks: the input track file.
- output: the output track-weighted image
Note: if you run into limitations with RAM usage, make sure you output the results to a .mif file or .mih / .dat file pair - this will avoid the allocation of an additional buffer to store the output for write-out.
Options for the header of the output image¶
- -template image an image file to be used as a template for the output (the output image will have the same transform and field of view).
- -vox size provide either an isotropic voxel size (in mm), or comma-separated list of 3 voxel dimensions.
- -datatype spec specify output image data type.
Options for the dimensionality of the output image¶
- -dec perform track mapping in directionally-encoded colour (DEC) space
- -dixel path map streamlines to dixels within each voxel; requires either a number of dixels (references an internal direction set), or a path to a text file containing a set of directions stored as azimuth/elevation pairs
- -tod lmax generate a Track Orientation Distribution (TOD) in each voxel; need to specify the maximum spherical harmonic degree lmax to use when generating Apodised Point Spread Functions
Options for the TWI image contrast properties¶
- -contrast type define the desired form of contrast for the output imageOptions are: tdi, length, invlength, scalar_map, scalar_map_count, fod_amp, curvature, vector_file (default: tdi)
- -image image provide the scalar image map for generating images with ‘scalar_map’ / ‘scalar_map_count’ contrast, or the spherical harmonics image for ‘fod_amp’ contrast
- -vector_file path provide the vector data file for generating images with ‘vector_file’ contrast
- -stat_vox type define the statistic for choosing the final voxel intensities for a given contrast type given the individual values from the tracks passing through each voxel. Options are: sum, min, mean, max (default: sum)
- -stat_tck type define the statistic for choosing the contribution to be made by each streamline as a function of the samples taken along their lengths. Only has an effect for ‘scalar_map’, ‘fod_amp’ and ‘curvature’ contrast types. Options are: sum, min, mean, max, median, mean_nonzero, gaussian, ends_min, ends_mean, ends_max, ends_prod (default: mean)
- -fwhm_tck value when using gaussian-smoothed per-track statistic, specify the desired full-width half-maximum of the Gaussian smoothing kernel (in mm)
- -map_zero if a streamline has zero contribution based on the contrast & statistic, typically it is not mapped; use this option to still contribute to the map even if this is the case (these non-contributing voxels can then influence the mean value in each voxel of the map)
Options for the streamline-to-voxel mapping mechanism¶
- -upsample factor upsample the tracks by some ratio using Hermite interpolation before mappping(If omitted, an appropriate ratio will be determined automatically)
- -precise use a more precise streamline mapping strategy, that accurately quantifies the length through each voxel (these lengths are then taken into account during TWI calculation)
- -ends_only only map the streamline endpoints to the image
- -tck_weights_in path specify a text scalar file containing the streamline weights
- -info display information messages.
- -quiet do not display information messages or progress status.
- -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)
- -failonwarn terminate program if a warning is produced
- -help display this information page and exit.
- -version display version information and exit.
- For TDI or DEC TDI:Calamante, F.; Tournier, J.-D.; Jackson, G. D. & Connelly, A. Track-density imaging (TDI): Super-resolution white matter imaging using whole-brain track-density mapping. NeuroImage, 2010, 53, 1233-1243
- If using -contrast length and -stat_vox mean:Pannek, K.; Mathias, J. L.; Bigler, E. D.; Brown, G.; Taylor, J. D. & Rose, S. E. The average pathlength map: A diffusion MRI tractography-derived index for studying brain pathology. NeuroImage, 2011, 55, 133-141
- If using -dixel option with TDI contrast only:Smith, R.E., Tournier, J-D., Calamante, F., Connelly, A. A novel paradigm for automated segmentation of very large whole-brain probabilistic tractography data sets. In proc. ISMRM, 2011, 19, 673
- If using -dixel option with any other contrast:Pannek, K., Raffelt, D., Salvado, O., Rose, S. Incorporating directional information in diffusion tractography derived maps: angular track imaging (ATI). In Proc. ISMRM, 2012, 20, 1912
- If using -tod option:Dhollander, T., Emsell, L., Van Hecke, W., Maes, F., Sunaert, S., Suetens, P. Track Orientation Density Imaging (TODI) and Track Orientation Distribution (TOD) based tractography. NeuroImage, 2014, 94, 312-336
- If using other contrasts / statistics:Calamante, F.; Tournier, J.-D.; Smith, R. E. & Connelly, A. A generalised framework for super-resolution track-weighted imaging. NeuroImage, 2012, 59, 2494-2503
- If using -precise mapping option:Smith, R. E.; Tournier, J.-D.; Calamante, F. & Connelly, A. SIFT: Spherical-deconvolution informed filtering of tractograms. NeuroImage, 2013, 67, 298-312 (Appendix 3)
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