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AFNI align_epi_anat — EPI-to-Anatomy Alignment

Library: AFNI | Docker Image: brainlife/afni

Function

Aligns EPI functional images to anatomical images with optional distortion correction using local Pearson correlation.

Modality: EPI volume (3D NIfTI) plus T1-weighted anatomical.

Typical Use: Core EPI-to-structural alignment in functional preprocessing.

Key Parameters

-epi (EPI dataset), -anat (anatomical), -epi_base (EPI reference volume), -cost (cost function, default lpc)

Key Points

lpc cost function designed for EPI-to-T1 alignment. Central tool in afni_proc.py.

Inputs

Name Type Required Label Flag
epi File Yes EPI dataset to align -epi
anat File Yes Anatomical dataset -anat
epi_base string Yes EPI base used in alignment (0/mean/median/max/subbrick#) -epi_base
anat2epi boolean No Align anatomical to EPI (default) -anat2epi
epi2anat boolean No Align EPI to anatomical instead -epi2anat
suffix string No Suffix to append to output names (default _al) -suffix
output_dir string No Output directory for results -output_dir
big_move boolean No Enable two-pass alignment for larger displacements -big_move
giant_move boolean No Even larger movement - uses cmass, two passes, very large angles -giant_move
ginormous_move boolean No Combines giant_move with center alignment -ginormous_move
rigid_body boolean No Limit transformation to translation and rotation only -rigid_body
volreg enum No Perform volume registration on EPI (default on) -volreg
tshift enum No Enable time-series correction (default on) -tshift
deoblique enum No Correct oblique dataset orientations (default on) -deoblique
cost string No Alignment cost function (default lpc) -cost
edge boolean No Use edge-detection method instead of standard cost -edge
save_all boolean No Preserve all intermediate datasets -save_all
save_vr boolean No Save motion-corrected EPI dataset -save_vr
save_skullstrip boolean No Save skull-stripped anatomy -save_skullstrip
anat_has_skull enum No Whether anatomical has skull -anat_has_skull
epi_strip enum No Method for stripping EPI -epi_strip

Accepted Input Extensions

  • epi: .nii, .nii.gz, +orig.HEAD, +orig.BRIK, +tlrc.HEAD, +tlrc.BRIK
  • anat: .nii, .nii.gz, +orig.HEAD, +orig.BRIK, +tlrc.HEAD, +tlrc.BRIK

Outputs

Name Type Glob Pattern
aligned_anat File *_al+orig.HEAD, *_al+tlrc.HEAD
aligned_epi File *_al_reg+orig.HEAD, *_al_reg+tlrc.HEAD
transform_matrix File[] *.aff12.1D
volreg_output File *_vr+orig.HEAD, *_vr+tlrc.HEAD
log File align_epi_anat.log

Output Extensions

  • aligned_anat: +orig.HEAD, +orig.BRIK, +tlrc.HEAD, +tlrc.BRIK
  • aligned_epi: +orig.HEAD, +orig.BRIK, +tlrc.HEAD, +tlrc.BRIK
  • transform_matrix: .aff12.1D
  • volreg_output: +orig.HEAD, +orig.BRIK, +tlrc.HEAD, +tlrc.BRIK

Docker Tags

Available versions: latest, 16.3.0

Categories

  • Functional MRI > AFNI > Registration

Documentation

Official Documentation