Index

Name

mri_label2label - converts a label in one subject's space to a label in another subject's space using either Talairach space or spherical space as an intermediate registration space

Synopsis

mri_label2label [<options>] --srcsubject srcsubject --srclabel srclabelfile --trgsubject trgsubject --trglabel trglabelfile --regmethod registrationmethod
mri_label2label [<options>] --srcsubject srcsubject --srclabel srclabelfile --trgsubject trgsubject --trglabel trglabelfile --regmethod surface --hemi hemisphere

Arguments

Required Flagged Arguments

--srcsubject srcsubject

source subject

--srclabel srclabelfile

input label file

--trgsubject trgsubject

target subject

--trglabel trglabel

output label file]

--regmethod registrationmethod

Legal values: surface, volume

Optional Flagged Arguments

--hemi hemisphere

(lh or rh)

required with --regmethod surface

--srchemi hemisphere

(lh or rh) (with surface)

--trghemi hemisphere

(lh or rh) (with surface)

--srcicoorder n

when srcsubject=ico

--trgicoorder n

when trgsubject=ico

--trgsurf

get xyz from this surface (white)

--surfreg srfregfile

surface registration (sphere.reg)]

--srcsurfreg srcsurfregfile

source surface registration (sphere.reg)

--trgsurfreg trgsurfregfile

target surface registration (sphere.reg)

--srcmask surfvalfile

--srcmasksign sign

Legal values: <abs>, pos, neg

--srcmaskframe frameno

0-based frame number. Default = 0.

--projabs dist

project dist mm along surf normal

--projfrac frac

project frac of thickness along surf normal

--sd subjectsdir

Default=SUBJECTS_DIR

--nohash

don not use hash table when regmethod is surface

--norevmap

do not use reverse mapping regmethod is surface

Outputs

??

??

Description

General

Converts a label in one subject's space to a label in another subject's space using either talairach or spherical as an intermediate registration space. If a source mask is used, then the input label must have been created from a surface (ie, the vertex numbers are valid). The format can be anything supported by mri_convert or curv or paint. Vertices in the source label that do not meet threshold in the mask will be removed from the label. See Example 2.

Notes

  1. A label can be converted to/from talairach space by specifying the target/source subject as 'talairach'.
  2. A label can be converted to/from the icosahedron by specifying the target/source subject as 'ico'. When the source or target subject is specified as 'ico', then the order of the icosahedron must be specified with --srcicoorder/--trgicoorder.
  3. When the surface registration method is used, the xyz coordinates in the target label file are derived from the xyz coordinates from the target subject's white surface. This can be changed using the --trgsurf option.
  4. When the volume registration method is used, the xyz coordinates in the target label file are computed as xyzTrg = inv(Ttrg)*Tsrc*xyzSrc where Tsrc is the talairach transform in srcsubject/mri/transforms/talairach.xfm, and where Ttrg is the talairach transform in trgsubject/mri/transforms/talairach.xfm.
  5. The registration surfaces are rescaled to a radius of 100 (including the ico)
  6. Projections along the surface normal can be either negative or positive, but can only be used with surface registration method.

Examples

Example 1

If you have a label from subject fred called broca-fred.label defined on fred's left hemispherical surface and you want to convert it to sally's surface, then

This will map from fred to sally using sphere.reg. The registration surface can be changed with --surfreg.

Example 2

Same as Example 1 but with a mask

This will load the bfloat data from fred-omnibus-sig and create a mask by thresholding the first frame absolute values at 2. To change it to only the positive values of the 3rd frame, add --srcmasksign pos --srcmaskframe 2

Example 3

You could also do the same mapping using talairach space as an intermediate:

Note that no hemisphere is specified with --regmethod volume.

Example 4

You have a label in the volume and you want to find the closest surface vertices:

This keeps the label on a single subject (but could also map to another subject). The label is mapped to vertices on the pial surface that are within 30mm of the label point. The xyz of the output label takes the coordinates of the pial surface (--trgsurf pial).

Bugs

When using volume registration method, you cannot specify the SUBJECTS_DIR on the command-line.

See Also

label_area, mri_mergelabels

Links

FreeSurfer, FsFast

Methods Description

References

Reporting Bugs

Report bugs to <analysis-bugs@nmr.mgh.harvard.edu>

Author/s

BruceFischl