cmtk-epiunwarp1
Unwarp echo planar images
Usage
epiunwarp InputImage1
InputImage2
OutputImage1
OutputImage2
OutputDField
OutputDFieldRev
Overview
Correct B0 field inhomogeneity-induced distortion in Echo Planar Images (e.g., diffusion-weighted images) using two images acquired with opposing phase encoding directions.
Options
Global Toolkit Options (these are shared by all CMTK tools)
-
--help -
Write list of basic command line options to standard output.
-
--help-all -
Write complete list of basic and advanced command line options to standard output.
-
--wiki -
Write list of command line options to standard output in MediaWiki markup.
-
--man -
Write man page source in 'nroff' markup to standard output.
-
--version -
Write toolkit version to standard output.
-
--echo -
Write the current command line to standard output.
-
--verbose-level <integer> -
Set verbosity level.
-
--verbose, -v -
Increment verbosity level by 1 (deprecated; supported for backward compatibility).
-
--threads <integer> -
Set maximum number of parallel threads (for POSIX threads and OpenMP).
Input Image Parameters
-
--phase-encode -
Define the phase-encoded image coordinate direction. Supported values: "phase-encode-ap", "phase-encode-is", "phase-encode-lr", where the default is "phase-encode-ap", or use one of the following:
-
--phase-encode-ap, -y -
Anterior/posterior phase encoding (this is the most common case) [This is the default]
-
--phase-encode-is, -z -
Top/bottom phase encoding (this is rare)
-
--phase-encode-lr, -x -
Lateral, left/right phase encoding (this is extremely rare)
-
-
--no-flip -
Use this switch is the reverse phase-encoded image does not need to be flipped prior to unwarping. If normal and reverse phase-encoded image display in the same gross orientation in 'triplanar', then flipping is not necessary and must be turned off using this switch.
Optimization Parameters
-
--no-init-shift-com -
Disable initialization of unwarping by shifting each row to align the centers of mass of forward and reverse acquisition. Instead, use all-zero initial deformation field.
-
--smooth-sigma-max <double> -
Maximum image smoothing kernel width for coarsest level of multi-scale computation. [Default: 8]
-
--smooth-sigma-min <double> -
Minimum image smoothing kernel width for finest level of multi-scale computation (0 = no smoothing; original image scale). [Default: 0]
-
--smooth-sigma-diff <double> -
Difference between image smoothing kernel widths between two successive levels of the multi-scale computation. [Default: 0.25]
-
--smoothness-constraint-weight <double> -
Weight factor for the second-order smoothness constraint term in the unwarping cost function. [Default: 0]
-
--folding-constraint-weight <double> -
Weight factor for the folding-prevention constraint term in the unwarping cost function. [Default: 0]
-
--iterations <integer>, -i <integer> -
Number of L-BFGS optimization iterations (per multi-scale level). [Default: 10]
Output Options
-
--write-jacobian-fwd <string> -
Write Jacobian intensity correction map for forward image. [Default: NONE]
-
--write-jacobian-rev <string> -
Write Jacobian intensity correction map for reverse-encoded image. [Default: NONE]
Acknowledgments
CMTK is developed with support from the NIAAA under Grant AA021697, National Consortium on Alcohol and Neurodevelopment in Adolescence (N-CANDA): Data Integration Component. From April 2009 through September 2011, CMTK development and maintenance was supported by the NIBIB under Grant EB008381.
History
- Debian 13 (Trixie): the text shown here
- Debian 12 (Bookworm)
- Debian 11 (Bullseye)
- Debian 10 (Buster)
- Debian 9 (Stretch)
- Debian 8 (Jessie)
- Debian 7 (Wheezy)
--no-flip since Debian 8 (Jessie).